1632 changed files with 38915 additions and 142561 deletions
--- a/.bazelrc
+++ b/.bazelrc
@ -1,26 +1,9 @@
-# Copyright The OpenTelemetry Authors
-# SPDX-License-Identifier: Apache-2.0
-
 # bazel configurations for running tests under sanitizers.
 # Based on https://github.com/bazelment/trunk/blob/master/tools/bazel.rc

-# Enable automatic configs based on platform
-common --enable_platform_specific_config
-
-# Make globs that don't match anything fail
-common --incompatible_disallow_empty_glob
-
 # Needed by gRPC to build on some platforms.
 build --copt -DGRPC_BAZEL_BUILD

-# Workaround abseil libraries missing symbols
-build:windows --dynamic_mode=off
-
-# Set minimum supported C++ version
-build:macos --host_cxxopt=-std=c++14 --cxxopt=-std=c++14
-build:linux --host_cxxopt=-std=c++14 --cxxopt=-std=c++14
-build:windows --host_cxxopt=/std:c++14 --cxxopt=/std:c++14
-
 # --config=asan : Address Sanitizer.
 common:asan --copt -DADDRESS_SANITIZER
 common:asan --copt -fsanitize=address,bool,float-cast-overflow,integer-divide-by-zero,null,return,returns-nonnull-attribute,shift-exponent,signed-integer-overflow,unreachable,vla-bound
@ -39,3 +22,4 @@ common:tsan --cc_output_directory_tag=tsan
 # This is needed to address false positive problem with abseil.The same setting as gRPC
 # https://github.com/google/sanitizers/issues/953
 common:tsan --test_env=TSAN_OPTIONS=report_atomic_races=0
+
--- a/.bazelversion
+++ b/.bazelversion
@ -1 +1 @@
-7.1.1
+4.2.0
--- a/.clang-format
+++ b/.clang-format
@ -1,6 +1,3 @@
-# Copyright The OpenTelemetry Authors
-# SPDX-License-Identifier: Apache-2.0
-
 # See Clang docs: http://clang.llvm.org/docs/ClangFormatStyleOptions.html
 BasedOnStyle: Chromium

@ -59,15 +56,3 @@ IndentPPDirectives: AfterHash

 # Include blocks style
 IncludeBlocks: Preserve
-
-AttributeMacros:
-  - OPENTELEMETRY_UNLIKELY
-  - OPENTELEMETRY_LIKELY
-  - OPENTELEMETRY_MAYBE_UNUSED
-  - OPENTELEMETRY_DEPRECATED
-  - OPENTELEMETRY_API_SINGLETON
-  - OPENTELEMETRY_LOCAL_SYMBOL
-  - OPENTELEMETRY_EXPORT
-  - OPENTELEMETRY_SANITIZER_NO_MEMORY
-  - OPENTELEMETRY_SANITIZER_NO_THREAD
-  - OPENTELEMETRY_SANITIZER_NO_ADDRESS
--- a/.clang-tidy
+++ b/.clang-tidy
@ -1,42 +0,0 @@
-# Copyright The OpenTelemetry Authors
-# SPDX-License-Identifier: Apache-2.0
-
-Checks: >
-  -*,
-  performance-*,
-  portability-*,
-  abseil-*,
-  -abseil-string-find-str-contains,
-  bugprone-*,
-  -bugprone-easily-swappable-parameters,
-  -bugprone-implicit-widening-of-multiplication-result,
-  -bugprone-inc-dec-in-conditions,
-  -bugprone-narrowing-conversions,
-  -bugprone-unchecked-optional-access,
-  -bugprone-unhandled-exception-at-new,
-  -bugprone-unused-local-non-trivial-variable,
-  google-*,
-  -google-build-using-namespace,
-  -google-default-arguments,
-  -google-explicit-constructor,
-  -google-readability-avoid-underscore-in-googletest-name,
-  -google-readability-braces-around-statements,
-  -google-readability-namespace-comments,
-  -google-readability-todo,
-  -google-runtime-references,
-  misc-*,
-  -misc-const-correctness,
-  -misc-include-cleaner,
-  -misc-non-private-member-variables-in-classes,
-  -misc-unused-alias-decls,
-  -misc-use-anonymous-namespace,
-  cppcoreguidelines-*,
-  -cppcoreguidelines-owning-memory,
-  -cppcoreguidelines-avoid-do-while,
-  -cppcoreguidelines-avoid-c-arrays,
-  -cppcoreguidelines-avoid-magic-numbers,
-  -cppcoreguidelines-init-variables,
-  -cppcoreguidelines-macro-usage,
-  -cppcoreguidelines-non-private-member-variables-in-classes,
-  -cppcoreguidelines-avoid-non-const-global-variables,
-  -cppcoreguidelines-pro-*
--- a/.cmake-format.py
+++ b/.cmake-format.py
@ -1,6 +1,3 @@
-# Copyright The OpenTelemetry Authors
-# SPDX-License-Identifier: Apache-2.0
-
 # If comment markup is enabled, don't reflow the first comment block in
 # eachlistfile. Use this to preserve formatting of your
 # copyright/licensestatements.
--- a/.copyright-ignore
+++ b/.copyright-ignore
@ -1,52 +0,0 @@
-# Copyright The OpenTelemetry Authors
-# SPDX-License-Identifier: Apache-2.0
-
-# Ignore the following directories
-
-./.git/*
-./.github/*
-./third_party/benchmark/*
-./third_party/boost/*
-./third_party/googletest/*
-./third_party/ms-gsl/*
-./third_party/nlohmann-json/*
-./third_party/opentelemetry-proto/*
-./third_party/prometheus-cpp/*
-./tools/vcpkg/*
-./tools/ports/*
-
-# Third party code
-
-./api/include/opentelemetry/nostd/internal/absl/*
-./exporters/jaeger/thrift-gen/*
-./exporters/etw/include/opentelemetry/exporters/etw/TraceLoggingDynamic.h
-
-# Doc
-
-./docs/*
-
-## Ignore the following files patterns
-
-*.md
-*.rst
-*.png
-*.log
-*.patch
-*.json
-*.nuspec
-*.pem
-
-# Packaging
-*/CONTROL
-
-# LICENSE files
-*/LICENSE
-
-# Ignore the following misc files
-
-./.bazelignore
-./.bazelversion
-./docker/.gitignore
-.markdownlintignore
-./ci/toc.yml
-./ci/valgrind-suppressions
--- a/.devcontainer/Dockerfile.conan
+++ b/.devcontainer/Dockerfile.conan
@ -1,55 +0,0 @@
-# Copyright The OpenTelemetry Authors
-# SPDX-License-Identifier: Apache-2.0
-FROM ubuntu:24.04@sha256:1e622c5f073b4f6bfad6632f2616c7f59ef256e96fe78bf6a595d1dc4376ac02
-
-RUN apt update && apt install -y \
-	build-essential \
-	ca-certificates \
-	wget \
-	cmake \
-	git \
-	sudo \
-	nano \
-	pkg-config \
-	ninja-build \
-	clang-format \
-	clang-tidy \
-	autoconf \
-	automake \
-	libtool \
-	python3-pip
-
-RUN pip install "conan==2.15.1" --break-system-packages
-
-ARG USER_UID=1000
-ARG USER_GID=1000
-ARG USER_NAME=devuser
-ENV USER_NAME=devuser
-ENV USER_UID=${USER_UID}
-ENV USER_GID=${USER_GID}
-ENV INSTALL_PACKAGES=
-ENV IS_CONTAINER_BUILD=true
-
-COPY ./.devcontainer/customize_container.sh /tmp/opentelemetry_cpp/devcontainer/customize_container.sh
-RUN /tmp/opentelemetry_cpp/devcontainer/customize_container.sh
-USER devuser
-
-RUN conan profile detect --force	
-
-ARG CONAN_FILE=conanfile_stable.txt
-ARG CONAN_BUILD_TYPE=Debug
-ARG CXX_STANDARD=17
-WORKDIR /home/devuser/conan
-COPY ./install/conan/ .
-
-RUN conan install ./${CONAN_FILE} --build=missing -s build_type=${CONAN_BUILD_TYPE}
-ENV CMAKE_TOOLCHAIN_FILE=/home/devuser/conan/build/${CONAN_BUILD_TYPE}/generators/conan_toolchain.cmake
-ENV CXX_STANDARD=${CXX_STANDARD}
-ENV BUILD_TYPE=${CONAN_BUILD_TYPE}
-ENV CONAN_FILE=${CONAN_FILE}
-
-WORKDIR  /workspaces/opentelemetry-cpp
-
-ENTRYPOINT []
-
-CMD ["/bin/bash"]
--- a/.devcontainer/Dockerfile.dev
+++ b/.devcontainer/Dockerfile.dev
@ -1,52 +0,0 @@
-# Copyright The OpenTelemetry Authors
-# SPDX-License-Identifier: Apache-2.0
-
-FROM otel/cpp_format_tools
-
-ARG USER_UID=1000
-ARG USER_GID=1000
-ARG INSTALL_PACKAGES=
-
-ARG CXX_STANDARD=17
-
-ENV CXX_STANDARD=${CXX_STANDARD}
-
-COPY ci /opt/ci
-
-RUN apt update && apt install -y wget \
-    ninja-build \
-    llvm-dev \
-    libclang-dev \
-    clang-tidy \
-    shellcheck \
-    sudo \
-    cmake
-
-RUN cd /opt/ci && bash setup_ci_environment.sh
-RUN cd /opt/ci && bash install_iwyu.sh
-
-ADD https://github.com/bazelbuild/bazelisk/releases/download/v1.22.1/bazelisk-linux-amd64 /usr/local/bin
-	
-RUN git config --global core.autocrlf input \
-	&& chmod +x /usr/local/bin/bazelisk-linux-amd64
-
-ENV INSTALL_PACKAGES=${INSTALL_PACKAGES}
-ENV USER_NAME=devuser
-ENV USER_UID=${USER_UID}
-ENV USER_GID=${USER_GID}
-ENV IS_CONTAINER_BUILD=true
-
-COPY install /opt/install
-COPY ./.devcontainer/customize_container.sh /tmp/opentelemetry_cpp/devcontainer/customize_container.sh
-RUN /tmp/opentelemetry_cpp/devcontainer/customize_container.sh
-RUN apt install -y npm && npm install -g markdownlint-cli@0.44.0
-
-USER devuser
-
-WORKDIR  /workspaces/opentelemetry-cpp
-RUN cd /opt && bash ci/install_thirdparty.sh --install-dir /home/devuser/third-party/install-stable --tags-file install/cmake/third_party_stable
-ENV CMAKE_PREFIX_PATH=/home/devuser/third-party/install-stable
-
-ENTRYPOINT []
-
-CMD ["/bin/bash"]
--- a/.devcontainer/README.md
+++ b/.devcontainer/README.md
@ -1,38 +0,0 @@
-# Customizing Your Dev Container
-
-Customize your dev container using build arguments (for direct Docker builds) or
-environment variables (for evaluation in `devcontainer.json`).
-
-* **CXX standard:**
-  This is the C++ standard to build from (eg: 17, 20, ...). (Default: 17)
-  * Docker ARG:
-   `CXX_STANDARD`
-  * Host Environment Variable:
-   `OTEL_CPP_DEVCONTAINER_CXX_STANDARD`
-
-* **User ID (UID):**
-  User ID (Default: `1000`)
-  * Docker ARG:
-   `USER_UID`
-  * Host Environment Variable:
-   `OTEL_CPP_DEVCONTAINER_USER_UID`
-
-* **Group ID (GID):**
-  User group ID (Default: `1000`)
-  * Docker ARG:
-   `USER_GID`
-  * Host Environment Variable:
-   `OTEL_CPP_DEVCONTAINER_USER_GID`
-
-* **Install Packages:**
-  These are the additional packages that will be installed via `apt install` in the devcontainer. This is a space separated list.
-  * Docker ARG:
-   `INSTALL_PACKAGES`  (Default: ``)
-  * Host Environment Variable:
-   `OTEL_CPP_DEVCONTAINER_INSTALL_PACKAGES` (Default: ``)
-
-## Examples
-
-* `docker build --build-arg CXX_STANDARD="20" --build-arg INSTALL_PACKAGES="nano gitk"...`
-* `export OTEL_CPP_DEVCONTAINER_CXX_STANDARD=20`
-* `export OTEL_CPP_DEVCONTAINER_INSTALL_PACKAGES="nano gitk"`
--- a/.devcontainer/customize_container.sh
+++ b/.devcontainer/customize_container.sh
@ -1,39 +0,0 @@
-#!/bin/bash
-
-# Copyright The OpenTelemetry Authors
-# SPDX-License-Identifier: Apache-2.0
-
-set -eu
-
-if [[ $IS_CONTAINER_BUILD != "true" ]]; then
-     echo "This script should only run inside a Docker container."
-     exit 1
-fi
-
-if [[ -n "$INSTALL_PACKAGES" ]]; then
-    packages=($INSTALL_PACKAGES)
-    for package in "${packages[@]}"; do
-        apt install -y "$package"
-    done
-fi
-
-if [[ $(id "$USER_NAME" 2>/dev/null) ]]; then
-    echo "User '$USER_NAME' already exists. Removing it."
-    userdel -rf "$USER_NAME"
-elif [[ $(id -u "$USER_UID" 2>/dev/null) ]]; then
-    OTHER_USER=$(getent passwd "$USER_UID" | cut -d: -f1)
-    echo "User '$OTHER_USER' exists with UID $USER_UID. Removing it."
-    userdel -rf "$OTHER_USER"
-fi
-
-if [[ ! $(getent group "$USER_GID" 2>/dev/null) ]]; then
-    echo "Group '$USER_GID' does not exist. Adding it."
-    groupadd -g "$USER_GID" "$USER_NAME"
-fi
-
-useradd -m -u "$USER_UID" -g "$USER_GID" -s /bin/bash "$USER_NAME"
-echo "Created user '$USER_NAME' (UID: $USER_UID, GID: $USER_GID)."
-
-echo "$USER_NAME ALL=(ALL) NOPASSWD:ALL" | tee /etc/sudoers.d/"$USER_NAME"
-
-echo "User and group setup complete."
--- a/.devcontainer/devcontainer.json
+++ b/.devcontainer/devcontainer.json
@ -1,31 +0,0 @@
-// Copyright The OpenTelemetry Authors
-// SPDX-License-Identifier: Apache-2.0
-// For format details, see https://aka.ms/devcontainer.json. For config options, see the README at:
-// https://github.com/microsoft/vscode-dev-containers/tree/v0.162.0/containers/javascript-node
-{
-	"name": "opentelemetry-cpp",
-	"build": {
-		"context": "..",
-		"dockerfile": "Dockerfile.dev",
-		"args": {
-			"USER_UID": "${localEnv:OTEL_CPP_DEVCONTAINER_USER_UID:1000}",
-			"USER_GID": "${localEnv:OTEL_CPP_DEVCONTAINER_USER_GID:1000}",
-			"INSTALL_PACKAGES": "${localEnv:OTEL_CPP_DEVCONTAINER_INSTALL_PACKAGES:}",
-			"CXX_STANDARD": "${localEnv:OTEL_CPP_DEVCONTAINER_CXX_STANDARD:17}"
-		}
-	},
-	"customizations": {
-		"vscode": {
-			"extensions": [
-				"ms-vscode.cpptools",
-				"ms-azuretools.vscode-docker",
-				"ms-vscode.cpptools-extension-pack"
-			],
-			"settings": {
-				"terminal.integrated.shell.linux": "/bin/bash",
-			}
-		}
-	},
-
-	"remoteUser": "devuser"
-}
--- a/.gitattributes
+++ b/.gitattributes
@ -41,7 +41,3 @@ LICENSE*                text
 ## git files
 .gitignore              text eol=lf
 .gitattributes          text eol=lf
-
-## bazel files
-WORKSPACE               text eol=lf
-BUILD                   text eol=lf
--- a/.github/.codecov.yaml
+++ b/.github/.codecov.yaml
@ -12,7 +12,11 @@ coverage:
        informational: true
        target: auto
        threshold: 10%
-    patch: false
+    patch:
+      default:
+        informational: true
+        target: auto
+        threshold: 10%

 parsers:
  gcov:
@ -33,18 +37,3 @@ comment:
 # to coverage report file paths.
 fixes:
  - "/home/runner/::"
-
-ignore:
-  - "docs/**/*"
-  - "docker/**/*"
-  - "examples/**/*"
-  - "bazel/**/*"
-  - "cmake/**/*"
-  - "buildscripts/**/*"
-  - "third_party/**/*"
-  - "test_common/**/*"
-  - "tools/**/*"
-  - ".vscode/**/*"
-  - ".github/**/*"
-  - "**/test/**/*"
-  - "**.md"
--- a/.github/ISSUE_TEMPLATE/bug_report.md
+++ b/.github/ISSUE_TEMPLATE/bug_report.md
@ -17,5 +17,3 @@ What did you see instead?

 **Additional context**
 Add any other context about the problem here.
-
-<sub>**Tip**: [React](https://github.blog/news-insights/product-news/add-reactions-to-pull-requests-issues-and-comments/) with 👍 to help prioritize this issue. Please use comments to provide useful context, avoiding `+1` or `me too`, to help us triage it. Learn more [here](https://opentelemetry.io/community/end-user/issue-participation/).</sub>
--- a/.github/ISSUE_TEMPLATE/feature_request.md
+++ b/.github/ISSUE_TEMPLATE/feature_request.md
@ -17,5 +17,3 @@ Which alternative solutions or features have you considered?

 **Additional context**
 Add any other context about the feature request here.
-
-<sub>**Tip**: [React](https://github.blog/news-insights/product-news/add-reactions-to-pull-requests-issues-and-comments/) with 👍 to help prioritize this issue. Please use comments to provide useful context, avoiding `+1` or `me too`, to help us triage it. Learn more [here](https://opentelemetry.io/community/end-user/issue-participation/).</sub>
--- a/.github/dependabot.yml
+++ b/.github/dependabot.yml
@ -1,13 +0,0 @@
-version: 2
-updates:
-  - package-ecosystem: "github-actions"
-    directory: "/"
-    schedule:
-      interval: "daily"
-    labels:
-      - "GHA"
-
-  - package-ecosystem: "devcontainers"
-    directory: "/"
-    schedule:
-     interval: daily
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@ -1,84 +0,0 @@
-name: OpenTelemetry-cpp benchmarks
-on:
-  push:
-    branches:
-      - main
-
-permissions:
-  contents: read
-
-jobs:
-  benchmark:
-    name: Run OpenTelemetry-cpp benchmarks
-    runs-on: ubuntu-latest
-    steps:
-      - name: Harden the runner (Audit all outbound calls)
-        uses: step-security/harden-runner@ec9f2d5744a09debf3a187a3f4f675c53b671911 # v2.13.0
-        with:
-          egress-policy: audit
-
-      - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
-        with:
-          submodules: 'recursive'
-      - name: Mount Bazel Cache
-        uses: actions/cache@0400d5f644dc74513175e3cd8d07132dd4860809 # v4.2.4
-        env:
-          cache-name: bazel_cache
-        with:
-          path: /home/runner/.cache/bazel
-          key: bazel_benchmark
-      - name: setup
-        run: |
-          sudo ./ci/setup_ci_environment.sh
-          sudo ./ci/install_bazelisk.sh
-      - name: Run benchmark
-        id: run_benchmarks
-        run: |
-          ./ci/do_ci.sh bazel.benchmark
-          mkdir -p benchmarks
-          mv api-benchmark_result.json benchmarks
-          mv sdk-benchmark_result.json benchmarks
-          mv exporters-benchmark_result.json benchmarks
-      - uses: actions/upload-artifact@6027e3dd177782cd8ab9af838c04fd81a07f1d47 # main March 2025
-        with:
-          name: benchmark_results
-          path: benchmarks
-  store_benchmark:
-    needs: benchmark
-    permissions:
-      contents: write
-      deployments: write
-    strategy:
-      matrix:
-        components: ["api", "sdk", "exporters"]
-    name: Store benchmark result
-    runs-on: ubuntu-latest
-    steps:
-      - name: Harden the runner (Audit all outbound calls)
-        uses: step-security/harden-runner@ec9f2d5744a09debf3a187a3f4f675c53b671911 # v2.13.0
-        with:
-          egress-policy: audit
-
-      - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
-      - uses: actions/download-artifact@634f93cb2916e3fdff6788551b99b062d0335ce0 # main March 2025
-        with:
-          name: benchmark_results
-          path: benchmarks
-      - name: Print json files
-        id: print_json
-        run: |
-          cat benchmarks/*
-      - name: Push benchmark result
-        uses: benchmark-action/github-action-benchmark@d48d326b4ca9ba73ca0cd0d59f108f9e02a381c7 # v1.20.4
-        with:
-          name: OpenTelemetry-cpp ${{ matrix.components }} Benchmark
-          tool: 'googlecpp'
-          output-file-path: benchmarks/${{ matrix.components }}-benchmark_result.json
-          github-token: ${{ secrets.GITHUB_TOKEN }}
-          auto-push: true
-          # Show alert with commit comment on detecting possible performance regression
-          alert-threshold: '200%'
-          comment-on-alert: true
-          fail-on-alert: false
-          gh-pages-branch: gh-pages
-          benchmark-data-dir-path: benchmarks
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
--- a/.github/workflows/clang-tidy.yaml
+++ b/.github/workflows/clang-tidy.yaml
@ -1,98 +0,0 @@
-name: clang-tidy
-
-on:
-  push:
-    branches: [main]
-  pull_request:
-    branches: [main]
-
-permissions:
-  contents: read
-
-jobs:
-  clang-tidy:
-    runs-on: ubuntu-latest
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - cmake_options: all-options-abiv1-preview
-            warning_limit: 61
-          - cmake_options: all-options-abiv2-preview
-            warning_limit: 61
-    steps:
-      - name: Harden the runner (Audit all outbound calls)
-        uses: step-security/harden-runner@ec9f2d5744a09debf3a187a3f4f675c53b671911 # v2.13.0
-        with:
-          egress-policy: audit
-
-      - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
-        with:
-          submodules: recursive
-
-      - name: Setup Environment
-        run: |
-          sudo apt update -y
-          sudo apt install -y --no-install-recommends --no-install-suggests \
-          build-essential \
-          cmake \
-          zlib1g-dev \
-          libssl-dev \
-          libcurl4-openssl-dev \
-          nlohmann-json3-dev \
-          libabsl-dev \
-          libprotobuf-dev \
-          libgrpc++-dev \
-          protobuf-compiler \
-          protobuf-compiler-grpc \
-          libgmock-dev \
-          libgtest-dev \
-          libbenchmark-dev
-
-          if ! command -v clang-tidy &> /dev/null; then
-            echo "clang-tidy could not be found"
-            exit 1
-          fi
-          echo "Using clang-tidy version: $(clang-tidy --version)"
-          echo "clang-tidy installed at: $(which clang-tidy)"
-
-      - name: Prepare CMake
-        env:
-          CC: clang
-          CXX: clang++
-        run: |
-          echo "Running cmake..."
-          cmake -B build-${{ matrix.cmake_options }} \
-            -C ./test_common/cmake/${{ matrix.cmake_options }}.cmake \
-            -DCMAKE_CXX_STANDARD=14 \
-            -DWITH_STL=CXX14 \
-            -DWITH_OPENTRACING=OFF \
-            -DCMAKE_CXX_FLAGS="-Wno-deprecated-declarations" \
-            -DCMAKE_EXPORT_COMPILE_COMMANDS=ON \
-            -DCMAKE_CXX_CLANG_TIDY="clang-tidy;--quiet;-p;build-${{ matrix.cmake_options }}"
-
-      - name: Run clang-tidy
-        run: |
-          cmake --build build-${{ matrix.cmake_options }} -- -j$(nproc) 2>&1 | tee clang-tidy-${{ matrix.cmake_options }}.log
-
-      - uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
-        with:
-          name: Logs-clang-tidy-${{ matrix.cmake_options }}
-          path: ./clang-tidy-${{ matrix.cmake_options }}.log
-
-      - name: Count warnings
-        run: |
-          COUNT=$(grep -c "warning:" clang-tidy-${{ matrix.cmake_options }}.log)
-          echo "clang-tidy reported ${COUNT} warning(s) with cmake options preset '${{ matrix.cmake_options }}'"
-
-          readonly WARNING_LIMIT=${{ matrix.warning_limit }}
-
-          # FAIL the build if COUNT > WARNING_LIMIT
-          if [ $COUNT -gt $WARNING_LIMIT ] ; then
-            echo "clang-tidy reported ${COUNT} warning(s) exceeding the existing warning limit of ${WARNING_LIMIT} with cmake options preset '${{ matrix.cmake_options }}'"
-            exit 1
-          # WARN in annotations if COUNT > 0
-          elif [ $COUNT -gt 0 ] ; then
-            echo "::warning::clang-tidy reported ${COUNT} warning(s) with cmake options preset '${{ matrix.cmake_options }}'"
-          fi
-
--- a/.github/workflows/cmake_install.yml
+++ b/.github/workflows/cmake_install.yml
@ -1,318 +0,0 @@
-name: CMake Install Tests
-
-on:
-  workflow_dispatch:
-  push:
-    branches: [ main ]
-  pull_request:
-    branches: [ main ]
-
-permissions:
-  contents: read
-
-jobs:
-  windows_2022_vcpkg_submodule:
-    name: Windows 2022 vcpkg submodule versions cxx17 (static libs - dll)
-    runs-on: windows-2022
-    env:
-      # cxx17 is the default for windows-2022
-      CXX_STANDARD: '17'
-    steps:
-      - name: Harden the runner (Audit all outbound calls)
-        uses: step-security/harden-runner@ec9f2d5744a09debf3a187a3f4f675c53b671911 # v2.13.0
-        with:
-          egress-policy: audit
-
-      - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
-        with:
-          submodules: 'recursive'
-      - name: Build dependencies with vcpkg submodule
-        run: |
-          ./ci/setup_windows_ci_environment.ps1
-      - name: Run Tests
-        run: ./ci/do_ci.ps1 cmake.install.test
-      - name: Run DLL Tests
-        run: ./ci/do_ci.ps1 cmake.dll.install.test
-
-  windows_2025_vcpkg_submodule:
-    name: Windows 2025 vcpkg submodule versions cxx20 (static libs)
-    runs-on: windows-2025
-    env:
-      CXX_STANDARD: '20'
-    steps:
-      - name: Harden the runner (Audit all outbound calls)
-        uses: step-security/harden-runner@ec9f2d5744a09debf3a187a3f4f675c53b671911 # v2.13.0
-        with:
-          egress-policy: audit
-
-      - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
-        with:
-          submodules: 'recursive'
-      - name: Build dependencies with vcpkg submodule
-        run: |
-          ./ci/setup_windows_ci_environment.ps1
-      - name: Run Tests
-        run: ./ci/do_ci.ps1 cmake.install.test
-
-  ubuntu_2404_system_packages:
-    name: Ubuntu 24.04 apt packages cxx17 (static libs - shared libs)
-    runs-on: ubuntu-24.04
-    env:
-      INSTALL_TEST_DIR: '/home/runner/install_test'
-      # cxx17 is the default for Ubuntu 24.04
-      CXX_STANDARD: '17'
-      BUILD_TYPE: 'Debug'
-    steps:
-    - name: Harden the runner (Audit all outbound calls)
-      uses: step-security/harden-runner@ec9f2d5744a09debf3a187a3f4f675c53b671911 # v2.13.0
-      with:
-        egress-policy: audit
-    - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
-      with:
-        submodules: 'recursive'
-    - name: Setup CI Environment
-      run: |
-        sudo -E ./ci/setup_ci_environment.sh
-    - name: Install Dependencies
-      run: |
-        sudo -E apt-get update
-        sudo -E apt-get install -y libabsl-dev libcurl4-openssl-dev zlib1g-dev nlohmann-json3-dev libprotobuf-dev libgrpc++-dev protobuf-compiler protobuf-compiler-grpc
-        sudo -E ./ci/install_thirdparty.sh --install-dir /usr/local --tags-file third_party_release --packages "googletest;benchmark"
-    - name: Run Tests (static libs)
-      env:
-        BUILD_SHARED_LIBS: 'OFF'
-      run: ./ci/do_ci.sh cmake.install.test
-    - name: Run Tests (shared libs)
-      env:
-        BUILD_SHARED_LIBS: 'ON'
-      run: ./ci/do_ci.sh cmake.install.test
-
-  ubuntu_2404_latest:
-    name: Ubuntu 24.04 latest versions cxx20 (static libs - shared libs)
-    runs-on: ubuntu-24.04
-    env:
-      INSTALL_TEST_DIR: '/home/runner/install_test'
-      CXX_STANDARD: '20'
-      BUILD_TYPE: 'Debug'
-    steps:
-    - name: Harden the runner (Audit all outbound calls)
-      uses: step-security/harden-runner@ec9f2d5744a09debf3a187a3f4f675c53b671911 # v2.13.0
-      with:
-        egress-policy: audit
-    - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
-      with:
-        submodules: 'recursive'
-    - name: Setup CI Environment
-      run: |
-        sudo -E ./ci/setup_ci_environment.sh
-    - name: Install Dependencies
-      run: |
-        sudo -E ./ci/install_thirdparty.sh --install-dir /usr/local --tags-file install/cmake/third_party_latest
-    - name: Run Tests (static libs)
-      env:
-        BUILD_SHARED_LIBS: 'OFF'
-      run: ./ci/do_ci.sh cmake.install.test
-    - name: Run Tests (shared libs)
-      env:
-        BUILD_SHARED_LIBS: 'ON'
-      run: ./ci/do_ci.sh cmake.install.test
-
-  ubuntu_2204_stable:
-    name: Ubuntu 22.04 stable versions cxx17 (static libs - shared libs)
-    runs-on: ubuntu-22.04
-    env:
-      INSTALL_TEST_DIR: '/home/runner/install_test'
-      CXX_STANDARD: '17'
-      BUILD_TYPE: 'Debug'
-    steps:
-    - name: Harden the runner (Audit all outbound calls)
-      uses: step-security/harden-runner@ec9f2d5744a09debf3a187a3f4f675c53b671911 # v2.13.0
-      with:
-        egress-policy: audit
-    - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
-      with:
-        submodules: 'recursive'
-    - name: Setup CI Environment
-      run: |
-        sudo -E ./ci/setup_ci_environment.sh
-    - name: Install Dependencies
-      run: |
-        sudo -E ./ci/install_thirdparty.sh --install-dir /usr/local --tags-file install/cmake/third_party_stable
-    - name: Run Tests (static libs)
-      env:
-        BUILD_SHARED_LIBS: 'OFF'
-      run: ./ci/do_ci.sh cmake.install.test
-    - name: Run Tests (shared libs)
-      env:
-        BUILD_SHARED_LIBS: 'ON'
-      run: ./ci/do_ci.sh cmake.install.test
-
-  ubuntu_2204_minimum:
-    name: Ubuntu 22.04 minimum versions cxx14 (static libs - shared libs)
-    runs-on: ubuntu-22.04
-    env:
-      INSTALL_TEST_DIR: '/home/runner/install_test'
-      # Set to the current minimum version of cmake
-      CMAKE_VERSION: '3.14.0'
-      # cxx14 is the default for Ubuntu 22.04
-      CXX_STANDARD: '14'
-      BUILD_TYPE: 'Debug'
-    steps:
-    - name: Harden the runner (Audit all outbound calls)
-      uses: step-security/harden-runner@ec9f2d5744a09debf3a187a3f4f675c53b671911 # v2.13.0
-      with:
-        egress-policy: audit
-    - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
-      with:
-        submodules: 'recursive'
-    - name: Setup CI Environment
-      run: |
-        sudo -E ./ci/setup_ci_environment.sh
-        sudo -E ./ci/setup_cmake.sh
-    - name: Install Dependencies
-      run: |
-        sudo -E ./ci/install_thirdparty.sh --install-dir /usr/local --tags-file install/cmake/third_party_minimum
-    - name: Run Tests (static libs)
-      env:
-          BUILD_SHARED_LIBS: 'OFF'
-      run: ./ci/do_ci.sh cmake.install.test
-    - name: Run Tests (shared libs)
-      env:
-          BUILD_SHARED_LIBS: 'ON'
-      run: ./ci/do_ci.sh cmake.install.test
-
-  ubuntu_2404_conan_stable:
-    name: Ubuntu 24.04 conan stable versions cxx17 (static libs - opentracing shim)
-    runs-on: ubuntu-24.04
-    env:
-      INSTALL_TEST_DIR: '/home/runner/install_test'
-      CXX_STANDARD: '17'
-      CMAKE_TOOLCHAIN_FILE: /home/runner/conan/build/Debug/generators/conan_toolchain.cmake
-      BUILD_TYPE: 'Debug'
-    steps:
-      - name: Harden the runner (Audit all outbound calls)
-        uses: step-security/harden-runner@ec9f2d5744a09debf3a187a3f4f675c53b671911 # v2.13.0
-        with:
-          egress-policy: audit
-
-      - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
-        with:
-          submodules: 'recursive'
-      - name: Install Conan
-        run: |
-          python3 -m pip install pip==25.0.1
-          pip install "conan==2.15.1"
-          conan profile detect --force
-      - name: Install or build all dependencies with Conan
-        run: |
-          conan install install/conan/conanfile_stable.txt --build=missing -of /home/runner/conan -s build_type=${BUILD_TYPE} -s compiler.cppstd=${CXX_STANDARD}
-          conan cache clean --source --build
-      - name: Run Tests (static libs)
-        env:
-          BUILD_SHARED_LIBS: 'OFF'
-        run: ./ci/do_ci.sh cmake.install.test
-      - name: verify pkgconfig packages
-        run: |
-          export PKG_CONFIG_PATH=$INSTALL_TEST_DIR/lib/pkgconfig:$PKG_CONFIG_PATH
-          ./ci/verify_packages.sh
-      - name: Run OpenTracing Shim Test
-        run: ./ci/do_ci.sh cmake.opentracing_shim.install.test
-
-  ubuntu_2404_conan_latest:
-    name: Ubuntu 24.04 conan latest versions cxx17 (static libs - opentracing shim)
-    runs-on: ubuntu-24.04
-    env:
-      INSTALL_TEST_DIR: '/home/runner/install_test'
-      CXX_STANDARD: '17'
-      CMAKE_TOOLCHAIN_FILE: /home/runner/conan/build/Debug/generators/conan_toolchain.cmake
-      BUILD_TYPE: 'Debug'
-    steps:
-      - name: Harden the runner (Audit all outbound calls)
-        uses: step-security/harden-runner@ec9f2d5744a09debf3a187a3f4f675c53b671911 # v2.13.0
-        with:
-          egress-policy: audit
-
-      - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
-        with:
-          submodules: 'recursive'
-      - name: Install Conan
-        run: |
-          python3 -m pip install pip==25.0.1
-          pip install "conan==2.15.1"
-          conan profile detect --force
-      - name: Install or build all dependencies with Conan
-        run: |
-          conan install install/conan/conanfile_latest.txt --build=missing -of /home/runner/conan -s build_type=${BUILD_TYPE} -s compiler.cppstd=${CXX_STANDARD}
-          conan cache clean --source --build
-      - name: Run Tests (static libs)
-        env:
-          BUILD_SHARED_LIBS: 'OFF'
-        run: ./ci/do_ci.sh cmake.install.test
-      - name: verify pkgconfig packages
-        run: |
-          export PKG_CONFIG_PATH=$INSTALL_TEST_DIR/lib/pkgconfig:$PKG_CONFIG_PATH
-          ./ci/verify_packages.sh
-      - name: Run OpenTracing Shim Test
-        run: ./ci/do_ci.sh cmake.opentracing_shim.install.test
-
-  macos_14_conan_stable:
-    name: macOS 14 conan stable versions cxx17 (static libs)
-    runs-on: macos-14
-    env:
-      INSTALL_TEST_DIR: '/Users/runner/install_test'
-      CXX_STANDARD: '17'
-      CMAKE_TOOLCHAIN_FILE: '/Users/runner/conan/build/Debug/generators/conan_toolchain.cmake'
-      BUILD_TYPE: 'Debug'
-    steps:
-    - name: Harden the runner (Audit all outbound calls)
-      uses: step-security/harden-runner@ec9f2d5744a09debf3a187a3f4f675c53b671911 # v2.13.0
-      with:
-        egress-policy: audit
-
-    - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
-      with:
-        submodules: 'recursive'
-    - name: Install Conan and tools
-      run: |
-        brew install conan autoconf automake libtool coreutils
-        conan profile detect --force
-    - name: Install or build all dependencies with Conan
-      run: |
-        conan install install/conan/conanfile_stable.txt --build=missing -of /Users/runner/conan -s build_type=${BUILD_TYPE} -s compiler.cppstd=${CXX_STANDARD}
-        conan cache clean --source --build
-    - name: Run Tests (static libs)
-      env:
-        BUILD_SHARED_LIBS: 'OFF'
-      run: ./ci/do_ci.sh cmake.install.test
-
-  macos_14_brew_packages:
-    name: macOS 14 brew latest versions cxx17 (static libs)
-    runs-on: macos-14
-    env:
-      INSTALL_TEST_DIR: '/Users/runner/install_test'
-      CXX_STANDARD: '17'
-      BUILD_TYPE: 'Debug'
-    steps:
-    - name: Harden the runner (Audit all outbound calls)
-      uses: step-security/harden-runner@ec9f2d5744a09debf3a187a3f4f675c53b671911 # v2.13.0
-      with:
-        egress-policy: audit
-
-    - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
-      with:
-        submodules: 'recursive'
-    - name: Install Dependencies with Homebrew
-      run: |
-        brew install coreutils
-        brew install googletest
-        brew install google-benchmark
-        brew install zlib
-        brew install abseil
-        brew install protobuf
-        brew install grpc
-        brew install nlohmann-json
-        brew install prometheus-cpp
-    - name: Run Tests (static libs)
-      env:
-        BUILD_SHARED_LIBS: 'OFF'
-      run: ./ci/do_ci.sh cmake.install.test
--- a/.github/workflows/codeql-analysis.yml
+++ b/.github/workflows/codeql-analysis.yml
@ -7,40 +7,26 @@ on:
    # The branches below must be a subset of the branches above
    branches: [main]

-permissions:
-  contents: read
-
 jobs:
  CodeQL-Build:
-    permissions:
-      actions: read  # for github/codeql-action/init to get workflow details
-      contents: read  # for actions/checkout to fetch code
-      security-events: write  # for github/codeql-action/autobuild to send a status report
    runs-on: ubuntu-latest
    steps:
-    - name: Harden the runner (Audit all outbound calls)
-      uses: step-security/harden-runner@ec9f2d5744a09debf3a187a3f4f675c53b671911 # v2.13.0
-      with:
-        egress-policy: audit
-
    - name: Checkout repository
-      uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
+      uses: actions/checkout@v2.3.4
      with:
         submodules: 'recursive'
    - name: Remove Third_party Modules from Code Scan
      run: |
        rm -rf third_party
    - name: Setup
-      env:
-        CC: /usr/bin/gcc-12
-        CXX: /usr/bin/g++-12
      run: |
-        sudo -E ./ci/setup_ci_environment.sh
+        sudo ./ci/setup_cmake.sh
+        sudo ./ci/setup_ci_environment.sh
    - name: Initialize CodeQL
-      uses: github/codeql-action/init@76621b61decf072c1cee8dd1ce2d2a82d33c17ed # v3.29.8
+      uses: github/codeql-action/init@v1
      with:
       languages: cpp
    - name: Autobuild
-      uses: github/codeql-action/autobuild@76621b61decf072c1cee8dd1ce2d2a82d33c17ed # v3.29.8
+      uses: github/codeql-action/autobuild@v1
    - name: Perform CodeQL Analysis
-      uses: github/codeql-action/analyze@76621b61decf072c1cee8dd1ce2d2a82d33c17ed # v3.29.8
+      uses: github/codeql-action/analyze@v1
--- a/.github/workflows/cppcheck.yml
+++ b/.github/workflows/cppcheck.yml
@ -1,77 +0,0 @@
-
-name: cppcheck
-
-on:
-  push:
-    branches: [ main ]
-  pull_request:
-    branches: [ main ]
-
-permissions:
-  contents: read
-
-jobs:
-  cppcheck:
-    runs-on: ubuntu-24.04
-    steps:
-      - name: Harden the runner (Audit all outbound calls)
-        uses: step-security/harden-runner@ec9f2d5744a09debf3a187a3f4f675c53b671911 # v2.13.0
-        with:
-          egress-policy: audit
-
-      - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
-        with:
-          submodules: 'recursive'
-
-      - name: Set up dependencies
-        run: |
-          sudo apt update -y
-          sudo apt install -y cppcheck
-
-      - name: Run cppcheck
-        run: |
-          cppcheck --version | tee cppcheck.log
-          cppcheck \
-            --force \
-            --enable=warning,performance,portability \
-            --inline-suppr \
-            --suppress=unknownMacro:exporters/etw/include/opentelemetry/exporters/etw/TraceLoggingDynamic.h \
-            --language=c++ \
-            --std=c++14 \
-            -I api/include \
-            -I exporters/elasticsearch/include \
-            -I exporters/etw/include \
-            -I exporters/memory/include \
-            -I exporters/ostream/include \
-            -I exporters/otlp/include \
-            -I exporters/prometheus/include \
-            -I exporters/zipkin/include \
-            -I ext/include \
-            -I opentracing-shim/include \
-            -I sdk/include \
-            -i build \
-            -i test \
-            -i third_party \
-            -j $(nproc) \
-            . 2>&1 | tee --append cppcheck.log
-
-      - uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
-        if: success() || failure()
-        with:
-          name: Logs (cppcheck)
-          path: ./cppcheck.log
-
-      - name: Count warnings
-        run: |
-          set +e
-          readonly WARNING_COUNT=`grep -c -E "\[.+\]" cppcheck.log`
-          echo "cppcheck reported ${WARNING_COUNT} warning(s)"
-          # Acceptable limit, to decrease over time down to 0
-          readonly WARNING_LIMIT=10
-          # FAIL the build if WARNING_COUNT > WARNING_LIMIT
-          if [ $WARNING_COUNT -gt $WARNING_LIMIT ] ; then
-            exit 1
-          # WARN in annotations if WARNING_COUNT > 0
-          elif [ $WARNING_COUNT -gt 0 ] ; then
-            echo "::warning::cppcheck reported ${WARNING_COUNT} warning(s)"
-          fi
--- a/.github/workflows/dependencies_image.yml
+++ b/.github/workflows/dependencies_image.yml
@ -1,54 +0,0 @@
-name: 'OpenTelemetry-cpp dependencies image'
-on:
-  schedule:
-    - cron: "0 3 * * 6"
-
-permissions:
-  contents: read
-
-jobs:
-  docker_image:
-    name: Docker Image
-    runs-on: ubuntu-latest
-    timeout-minutes: 300
-    steps:
-    - name: Harden the runner (Audit all outbound calls)
-      uses: step-security/harden-runner@ec9f2d5744a09debf3a187a3f4f675c53b671911 # v2.13.0
-      with:
-        egress-policy: audit
-
-    -
-      name: checkout
-      uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
-    -
-      name: Set up QEMU
-      uses: docker/setup-qemu-action@29109295f81e9208d7d86ff1c6c12d2833863392 # v3.6.0
-    -
-      name: Set up Docker Buildx
-      id: buildx
-      uses: docker/setup-buildx-action@e468171a9de216ec08956ac3ada2f0791b6bd435 # v3.11.1
-    -
-      name: Build Image
-      uses: docker/build-push-action@263435318d21b8e681c14492fe198d362a7d2c83 # v6.18.0
-      with:
-        builder: ${{ steps.buildx.outputs.name }}
-        context: ci/
-        file: ./docker/Dockerfile
-        build-args: BASE_IMAGE=ubuntu:latest
-        platforms: linux/amd64
-        # platforms: linux/amd64,linux/arm64
-        push: false
-        tags: otel-cpp-deps
-        load: true
-    -
-      name: Save Image
-      run: |
-        docker images
-        docker save -o /opt/otel-cpp-deps-debian.tar otel-cpp-deps
-    -
-      name: Upload Image
-      uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
-      with:
-        name: otel-cpp-deps
-        path: /opt/otel-cpp-deps-debian.tar
-        retention-days: 14
--- a/.github/workflows/fossa.yml
+++ b/.github/workflows/fossa.yml
@ -1,25 +0,0 @@
-name: FOSSA scanning
-
-on:
-  push:
-    branches:
-      - main
-
-permissions:
-  contents: read
-
-jobs:
-  fossa:
-    runs-on: ubuntu-latest
-    steps:
-      - name: Harden the runner (Audit all outbound calls)
-        uses: step-security/harden-runner@ec9f2d5744a09debf3a187a3f4f675c53b671911 # v2.13.0
-        with:
-          egress-policy: audit
-
-      - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
-
-      - uses: fossas/fossa-action@3ebcea1862c6ffbd5cf1b4d0bd6b3fe7bd6f2cac # v1.7.0
-        with:
-          api-key: ${{secrets.FOSSA_API_KEY}}
-          team: OpenTelemetry
--- a/.github/workflows/iwyu.yml
+++ b/.github/workflows/iwyu.yml
@ -1,98 +0,0 @@
-
-name: include-what-you-use
-
-on:
-  push:
-    branches: [ main ]
-  pull_request:
-    branches: [ main ]
-
-permissions:
-  contents: read
-
-jobs:
-  iwyu:
-    runs-on: ubuntu-latest
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - cmake_options: all-options-abiv1
-            warning_limit: 0
-          - cmake_options: all-options-abiv1-preview
-            warning_limit: 0
-          - cmake_options: all-options-abiv2-preview
-            warning_limit: 0
-
-    steps:
-      - name: Harden the runner (Audit all outbound calls)
-        uses: step-security/harden-runner@ec9f2d5744a09debf3a187a3f4f675c53b671911 # v2.13.0
-        with:
-          egress-policy: audit
-
-      - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
-        with:
-          submodules: 'recursive'
-
-      - name: setup dependencies
-        run: |
-          sudo apt update -y
-          sudo apt install -y --no-install-recommends --no-install-suggests \
-            build-essential \
-            ninja-build \
-            libssl-dev \
-            libcurl4-openssl-dev \
-            libabsl-dev \
-            libprotobuf-dev \
-            libgrpc++-dev \
-            protobuf-compiler \
-            protobuf-compiler-grpc \
-            libgmock-dev \
-            libgtest-dev \
-            libbenchmark-dev \
-            llvm-dev \
-            libclang-dev \
-            cmake
-      - name: Install include-what-you-use
-        run: |
-          sudo ./ci/install_iwyu.sh
-      - name: Prepare CMake
-        env:
-          CC: clang
-          CXX: clang++
-        run: |
-          TOPDIR=`pwd`
-          cmake -B build-${{ matrix.cmake_options }} \
-            -C ./test_common/cmake/${{ matrix.cmake_options }}.cmake \
-            -DCMAKE_CXX_STANDARD=14 \
-            -DWITH_STL=CXX14 \
-            -DCMAKE_CXX_FLAGS="-Wno-deprecated-declarations" \
-            -DCMAKE_CXX_INCLUDE_WHAT_YOU_USE="include-what-you-use;-w;-Xiwyu;--mapping_file=${TOPDIR}/.iwyu.imp;"
-
-      - name: iwyu_tool
-        run: |
-          cmake --build build-${{ matrix.cmake_options }} -- -j$(nproc) -k 2>&1 | tee -a iwyu-${{ matrix.cmake_options }}.log
-
-      - uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
-        if: success() || failure()
-        with:
-          name: Logs-iwyu-${{ matrix.cmake_options }}
-          path: ./iwyu-${{ matrix.cmake_options }}.log
-
-      - name: count warnings
-        run: |
-          set +e
-          echo "include-what-you-use version:"
-          include-what-you-use --version
-          readonly WARNING_COUNT=`grep -c "include-what-you-use reported diagnostics:" iwyu-${{ matrix.cmake_options }}.log`
-          echo "include-what-you-use reported ${WARNING_COUNT} warning(s) with cmake options preset '${{ matrix.cmake_options }}'"
-          # Acceptable limit, to decrease over time down to 0
-          readonly WARNING_LIMIT=${{ matrix.warning_limit }}
-          # FAIL the build if WARNING_COUNT > WARNING_LIMIT
-          if [ $WARNING_COUNT -gt $WARNING_LIMIT ] ; then
-            echo "include-what-you-use reported ${WARNING_COUNT} warning(s) exceeding the existing warning limit of ${WARNING_LIMIT} with cmake options preset '${{ matrix.cmake_options }}'"
-            exit 1
-          # WARN in annotations if WARNING_COUNT > 0
-          elif [ $WARNING_COUNT -gt 0 ] ; then
-            echo "::warning::include-what-you-use reported ${WARNING_COUNT} warning(s) with cmake options preset '${{ matrix.cmake_options }}'"
-          fi
--- a/.github/workflows/ossf-scorecard.yml
+++ b/.github/workflows/ossf-scorecard.yml
@ -1,52 +0,0 @@
-name: OSSF Scorecard
-
-on:
-  push:
-    branches:
-      - main
-  schedule:
-    - cron: "56 23 * * 6" # once a week
-  workflow_dispatch:
-
-permissions: read-all
-
-jobs:
-  analysis:
-    runs-on: ubuntu-latest
-    permissions:
-      # Needed for Code scanning upload
-      security-events: write
-      # Needed for GitHub OIDC token if publish_results is true
-      id-token: write
-    steps:
-      - name: Harden the runner (Audit all outbound calls)
-        uses: step-security/harden-runner@ec9f2d5744a09debf3a187a3f4f675c53b671911 # v2.13.0
-        with:
-          egress-policy: audit
-
-      - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
-        with:
-          persist-credentials: false
-
-      - uses: ossf/scorecard-action@05b42c624433fc40578a4040d5cf5e36ddca8cde # v2.4.2
-        with:
-          results_file: results.sarif
-          results_format: sarif
-          publish_results: true
-
-      # Upload the results as artifacts (optional). Commenting out will disable
-      # uploads of run results in SARIF format to the repository Actions tab.
-      # https://docs.github.com/en/actions/advanced-guides/storing-workflow-data-as-artifacts
-      - name: "Upload artifact"
-        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
-        with:
-          name: SARIF file
-          path: results.sarif
-          retention-days: 5
-
-      # Upload the results to GitHub's code scanning dashboard (optional).
-      # Commenting out will disable upload of results to your repo's Code Scanning dashboard
-      - name: "Upload to code-scanning"
-        uses: github/codeql-action/upload-sarif@76621b61decf072c1cee8dd1ce2d2a82d33c17ed # v3.29.8
-        with:
-          sarif_file: results.sarif
--- a/.github/workflows/project_management_comment.yml
+++ b/.github/workflows/project_management_comment.yml
@ -1,28 +0,0 @@
-
-name: Add comment
-on:
-  issues:
-    types:
-      - labeled
-permissions:
-  contents: read
-
-jobs:
-  add-comment:
-    if: github.event.label.name == 'help wanted'
-    runs-on: ubuntu-latest
-    permissions:
-      issues: write
-    steps:
-      - name: Harden the runner (Audit all outbound calls)
-        uses: step-security/harden-runner@ec9f2d5744a09debf3a187a3f4f675c53b671911 # v2.13.0
-        with:
-          egress-policy: audit
-
-      - name: Add comment
-        uses: peter-evans/create-or-update-comment@71345be0265236311c031f5c7866368bd1eff043
-        with:
-          issue-number: ${{ github.event.issue.number }}
-          body: |
-            This issue is available for anyone to work on. **Make sure to reference this issue in your pull request.**
-            :sparkles: Thank you for your contribution! :sparkles:
--- a/.github/workflows/project_management_issue_open.yml
+++ b/.github/workflows/project_management_issue_open.yml
@ -1,29 +0,0 @@
-name: OpenTelemetry-cpp project
-on:
-  issues:
-    types:
-      - reopened
-      - opened
-permissions:
-  contents: read
-
-jobs:
-  label_issues:
-    runs-on: ubuntu-latest
-    permissions:
-      issues: write
-    steps:
-      - name: Harden the runner (Audit all outbound calls)
-        uses: step-security/harden-runner@ec9f2d5744a09debf3a187a3f4f675c53b671911 # v2.13.0
-        with:
-          egress-policy: audit
-
-      - uses: actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea # v7.0.1
-        with:
-          script: |
-            github.rest.issues.addLabels({
-              issue_number: context.issue.number,
-              owner: context.repo.owner,
-              repo: context.repo.repo,
-              labels: ["needs-triage"]
-            })
--- a/.github/workflows/stale.yml
+++ b/.github/workflows/stale.yml
@ -1,21 +1,16 @@
-name: "Mark stale issues"
+name: 'Mark and close stale issues'
 on:
  schedule:
-    - cron: "30 1 * * *"
-
-permissions:
-  contents: read
+    - cron: '30 1 * * *'

 jobs:
  stale:
-    permissions:
-      issues: write  # for actions/stale to close stale issues
-      pull-requests: write  # for actions/stale to close stale PRs
    runs-on: ubuntu-latest
    steps:
-      - uses: actions/stale@5bef64f19d7facfb25b37b414482c7164d639639 # v9.1.0
+      - uses: actions/stale@v4
        with:
-          stale-issue-message: "This issue was marked as stale due to lack of activity."
+          stale-issue-message: 'This issue was marked as stale due to lack of activity. It will be closed in 7 days if no furthur activity occurs.'
+          close-issue-message: 'Closed as inactive. Feel free to reopen if this is still an issue.'
          days-before-issue-stale: 60
-          days-before-close: -1
-          exempt-issue-labels: "do-not-stale"
+          days-before-issue-close: 7
+          exempt-pr-labels: 'do-not-stale'
--- a/.gitignore
+++ b/.gitignore
@ -1,6 +1,3 @@
-# Copyright The OpenTelemetry Authors
-# SPDX-License-Identifier: Apache-2.0
-
 # Ref. https://github.com/github/gitignore/blob/master/C%2B%2B.gitignore
 # Prerequisites
 *.d
@ -19,7 +16,6 @@
 *.so
 *.dylib
 *.dll
-*.pdb

 # Fortran module files
 *.mod
@ -37,7 +33,6 @@
 *.app

 # Bazel files
-MODULE.bazel.lock
 /bazel-*

 # Mac
@ -53,30 +48,3 @@ MODULE.bazel.lock
 /bazel-*
 /plugin
 /build
-
-tags
-.cache/clangd/*
-
-# Temporary dir used when generating semconv
-buildscripts/semantic-convention/tmp-semconv/
-
-# Generated cert keys in functional tests
-functional/cert/ca.csr
-functional/cert/ca.pem
-functional/cert/ca-key.pem
-functional/cert/client_cert.csr
-functional/cert/client_cert.pem
-functional/cert/client_cert-key.pem
-functional/cert/server_cert.csr
-functional/cert/server_cert.pem
-functional/cert/server_cert-key.pem
-functional/cert/ca_b.csr
-functional/cert/ca_b.pem
-functional/cert/ca_b-key.pem
-functional/cert/client_cert_b.csr
-functional/cert/client_cert_b.pem
-functional/cert/client_cert_b-key.pem
-functional/cert/server_cert_b.csr
-functional/cert/server_cert_b.pem
-functional/cert/server_cert_b-key.pem
-functional/cert/unreadable.pem
--- a/.gitmodules
+++ b/.gitmodules
@ -1,39 +1,34 @@
 [submodule "third_party/prometheus-cpp"]
-path = third_party/prometheus-cpp
-url = https://github.com/jupp0r/prometheus-cpp
-branch = master
+	path = third_party/prometheus-cpp
+	url = https://github.com/jupp0r/prometheus-cpp
+	branch = master

 [submodule "tools/vcpkg"]
-path = tools/vcpkg
-url = https://github.com/Microsoft/vcpkg
-branch = master
+	path = tools/vcpkg
+	url = https://github.com/Microsoft/vcpkg
+	branch = master

 [submodule "third_party/ms-gsl"]
-path = third_party/ms-gsl
-url = https://github.com/microsoft/GSL
-branch = main
+	path = third_party/ms-gsl
+	url = https://github.com/microsoft/GSL
+	branch = master

 [submodule "third_party/googletest"]
-path = third_party/googletest
-url = https://github.com/google/googletest
-branch = main
+	path = third_party/googletest
+	url = https://github.com/google/googletest
+	branch = master

 [submodule "third_party/benchmark"]
-path = third_party/benchmark
-url = https://github.com/google/benchmark
-branch = main
+	path = third_party/benchmark
+	url = https://github.com/google/benchmark
+	branch = master

 [submodule "third_party/opentelemetry-proto"]
-path = third_party/opentelemetry-proto
-url = https://github.com/open-telemetry/opentelemetry-proto
-branch = main
+	path = third_party/opentelemetry-proto
+	url = https://github.com/open-telemetry/opentelemetry-proto
+	branch = master

 [submodule "third_party/nlohmann-json"]
-path = third_party/nlohmann-json
-url = https://github.com/nlohmann/json
-branch = master
-
-[submodule "third_party/opentracing-cpp"]
-path = third_party/opentracing-cpp
-url = https://github.com/opentracing/opentracing-cpp.git
-branch = master
+	path = third_party/nlohmann-json
+	url = https://github.com/nlohmann/json
+	branch = master
--- a/.iwyu.imp
+++ b/.iwyu.imp
@ -1,31 +0,0 @@
-# Copyright The OpenTelemetry Authors
-# SPDX-License-Identifier: Apache-2.0
-
-# include-what-you-use mapping file
-
-[
-  # Work around for C++ STL
-  { "include": ["<bits/chrono.h>", "private", "<chrono>", "public"] },
-  { "include": ["<bits/std_abs.h>", "private", "<cstdlib>", "public"] },
-  { "include": ["<ext/alloc_traits.h>", "private", "<memory>", "public"] },
-  { "include": ["<bits/types/struct_tm.h>", "private", "<time.h>", "public"] },
-  { "include": ["<bits/types/struct_FILE.h>", "private", "<stdio.h>", "public"] },
-
-  # Local opentelemetry-cpp style
-
-  # We prefer to include <gtest/gtest.h> for simplicity
-  { "include": ["<gtest/gtest-message.h>", "private", "<gtest/gtest.h>", "public"] },
-  { "include": ["<gtest/gtest-test-part.h>", "private", "<gtest/gtest.h>", "public"] },
-  { "include": ["<gtest/gtest-param-test.h>", "private", "<gtest/gtest.h>", "public"] },
-  { "include": ["<gtest/gtest_pred_impl.h>", "private", "<gtest/gtest.h>", "public"] },
-  { "include": ["<gtest/gtest-typed-test.h>", "private", "<gtest/gtest.h>", "public"] },
-  { "include": ["<gtest/gtest-assertion-result.h>", "private", "<gtest/gtest.h>", "public"] },
-
-  # We prefer to include <gmock/gmock.h> for simplicity
-  { "include": ["<gmock/gmock-function-mocker.h>", "private", "<gmock/gmock.h>", "public"] },
-  { "include": ["<gmock/gmock-spec-builders.h>", "private", "<gmock/gmock.h>", "public"] },
-
-  # We prefer to include <curl/curl.h> for simplicity
-  { "include": ["<curl/system.h>", "private", "<curl/curl.h>", "public"] },
-]
-
--- a/.markdownlint.json
+++ b/.markdownlint.json
@ -1,8 +1,4 @@
 {
    "default": true,
-    "MD013":
-    {
-        "code_blocks": false,
-        "tables": false
-    }
+    "line-length": false
 }
--- a/.vscode/launch.json
+++ b/.vscode/launch.json
@ -1,33 +0,0 @@
-{
-  "version": "0.2.0",
-  "configurations": [
-    {
-        "name": "(ctest) Launch",
-        "type": "cppdbg",
-        "cwd": "${cmake.testWorkingDirectory}",
-        "request": "launch",
-        "program": "${cmake.testProgram}",
-        "args": [ "${cmake.testArgs}" ],
-        // other options...
-    },
-    {
-        "name": "Debug on Windows",
-        "type": "cppvsdbg",
-        "request": "launch",
-        "program": "${workspaceFolder}/build/<path-to-bin-file>",
-        "args": [],
-        "stopAtEntry": false,
-        "cwd": "${workspaceFolder}",
-        "environment": [],
-        "externalConsole": false
-    },
-    {
-        "name": "Debug on Linux",
-        "type": "gdb",
-        "request": "launch",
-        "target": "${workspaceFolder}/bazel-bin/<path to the bin file>",
-        "cwd": "${workspaceRoot}",
-        "valuesFormatting": "parseText"
-    }
-  ]
-}
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@ -1,36 +1,15 @@
-# Copyright The OpenTelemetry Authors
-# SPDX-License-Identifier: Apache-2.0
+cmake_minimum_required(VERSION 3.1)

-cmake_minimum_required(VERSION 3.14)
+# See https://cmake.org/cmake/help/v3.3/policy/CMP0057.html required by certain
+# versions of gtest
+cmake_policy(SET CMP0057 NEW)

-# See https://cmake.org/cmake/help/latest/policy/CMP0074.html required by
-# certain version of zlib which CURL depends on.
+# See https://cmake.org/cmake/help/v3.12/policy/CMP0074.html required by certain
+# version of zlib which is dependeded by cURL.
 if(${CMAKE_VERSION} VERSION_GREATER_EQUAL "3.12")
  cmake_policy(SET CMP0074 NEW)
 endif()

-# Allow to use normal variable for option()
-if(${CMAKE_VERSION} VERSION_GREATER_EQUAL "3.13")
-  cmake_policy(SET CMP0077 NEW)
-endif()
-
-# Prefer CMAKE_MSVC_RUNTIME_LIBRARY if possible
-if(POLICY CMP0091)
-  cmake_policy(SET CMP0091 NEW)
-endif()
-
-if(POLICY CMP0092)
-  # https://cmake.org/cmake/help/latest/policy/CMP0092.html#policy:CMP0092 Make
-  # sure the /W3 is not removed from CMAKE_CXX_FLAGS since CMake 3.15
-  cmake_policy(SET CMP0092 OLD)
-endif()
-
-# MSVC RTTI flag /GR should not be not added to CMAKE_CXX_FLAGS by default. @see
-# https://cmake.org/cmake/help/latest/policy/CMP0117.html
-if(CMAKE_VERSION VERSION_GREATER_EQUAL "3.20.0")
-  cmake_policy(SET CMP0117 NEW)
-endif()
-
 project(opentelemetry-cpp)

 # Mark variables as used so cmake doesn't complain about them
@ -41,32 +20,56 @@ if(NOT DEFINED CMAKE_TOOLCHAIN_FILE)
  list(APPEND CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/cmake/modules/")
 endif()

-# Set the third-party release git tags.
-if(EXISTS "${opentelemetry-cpp_SOURCE_DIR}/third_party_release")
-  file(STRINGS "${opentelemetry-cpp_SOURCE_DIR}/third_party_release"
-       third_party_tags)
-  foreach(_raw_line IN LISTS third_party_tags)
-    # Strip leading/trailing whitespace
-    string(STRIP "${_raw_line}" _line)
-    # Skip empty lines and comments
-    if(_line STREQUAL "" OR _line MATCHES "^#")
-      continue()
-    endif()
-
-    # Match "package_name=git_tag"
-    if(_line MATCHES "^([^=]+)=(.+)$")
-      set(_third_party_name "${CMAKE_MATCH_1}")
-      set(_git_tag "${CMAKE_MATCH_2}")
-      set("${_third_party_name}_GIT_TAG" "${_git_tag}")
-    else()
-      message(
-        FATAL_ERROR
-          "Could not parse third-party tag. Invalid line in ${opentelemetry-cpp_SOURCE_DIR}/third_party_release. Line:\n  ${_raw_line}"
-      )
-    endif()
+if(EXISTS "${CMAKE_SOURCE_DIR}/third_party_release")
+  file(STRINGS "${CMAKE_SOURCE_DIR}/third_party_release" third_party_tags)
+  foreach(third_party ${third_party_tags})
+    string(REGEX REPLACE "^[ ]+" "" third_party ${third_party})
+    string(REGEX MATCH "^[^=]+" third_party_name ${third_party})
+    string(REPLACE "${third_party_name}=" "" third_party_tag ${third_party})
+    set(${third_party_name} "${third_party_tag}")
  endforeach()
 endif()

+if(DEFINED ENV{ARCH})
+  # Architecture may be specified via ARCH environment variable
+  set(ARCH $ENV{ARCH})
+else()
+  # Autodetection logic that populates ARCH variable
+  if(CMAKE_SYSTEM_PROCESSOR MATCHES "amd64.*|x86_64.*|AMD64.*")
+    # Windows may report AMD64 even if target is 32-bit
+    if(CMAKE_SIZEOF_VOID_P EQUAL 8)
+      set(ARCH x64)
+    elseif(CMAKE_SIZEOF_VOID_P EQUAL 4)
+      set(ARCH x86)
+    endif()
+  elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "i686.*|i386.*|x86.*")
+    # Windows may report x86 even if target is 64-bit
+    if(CMAKE_SIZEOF_VOID_P EQUAL 8)
+      set(ARCH x64)
+    elseif(CMAKE_SIZEOF_VOID_P EQUAL 4)
+      set(ARCH x86)
+    endif()
+  elseif(CMAKE_SYSTEM_PROCESSOR MATCHES
+         "^(aarch64.*|AARCH64.*|arm64.*|ARM64.*)")
+    set(ARCH arm64)
+  elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "^(arm.*|ARM.*)")
+    set(ARCH arm)
+  elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "^(powerpc|ppc)64le")
+    set(ARCH ppc64le)
+  elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "^(powerpc|ppc)64")
+    set(ARCH ppc64)
+  elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "^(mips.*|MIPS.*)")
+    set(ARCH mips)
+  elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "^(riscv.*|RISCV.*)")
+    set(ARCH riscv)
+  else()
+    message(
+      FATAL_ERROR
+        "opentelemetry-cpp: unrecognized target processor configuration!")
+  endif()
+endif()
+message(STATUS "Building for architecture ARCH=${ARCH}")
+
 # Autodetect vcpkg toolchain
 if(DEFINED ENV{VCPKG_ROOT} AND NOT DEFINED CMAKE_TOOLCHAIN_FILE)
  set(CMAKE_TOOLCHAIN_FILE
@ -74,54 +77,21 @@ if(DEFINED ENV{VCPKG_ROOT} AND NOT DEFINED CMAKE_TOOLCHAIN_FILE)
      CACHE STRING "")
 endif()

-option(WITH_ABI_VERSION_1 "ABI version 1" ON)
-option(WITH_ABI_VERSION_2 "EXPERIMENTAL: ABI version 2 preview" OFF)
+if(VCPKG_CHAINLOAD_TOOLCHAIN_FILE)
+  include("${VCPKG_CHAINLOAD_TOOLCHAIN_FILE}")
+endif()

 file(READ "${CMAKE_CURRENT_LIST_DIR}/api/include/opentelemetry/version.h"
     OPENTELEMETRY_CPP_HEADER_VERSION_H)
-
-#
-# We do not want to have WITH_ABI_VERSION = "1" or "2", and instead prefer two
-# distinct flags, WITH_ABI_VERSION_1 and WITH_ABI_VERSION_2.
-#
-# This allows:
-#
-# * to have a specific option description for each ABI
-# * to mark experimental/stable/deprecated on flags, for clarity
-# * to search for exact abi usage move easily, discouraging:
-#
-#   * cmake -DWITH_ABI_VERSION=${ARG}
-#
-# While not supported, having distinct WITH_ABI_VERSION_1 and WITH_ABI_VERSION_2
-# flags also opens the possibility to support multiple ABI concurrently, should
-# that become necessary.
-#
-if(WITH_ABI_VERSION_1 AND WITH_ABI_VERSION_2)
-  #
-  # Only one ABI is supported in a build.
-  #
-  message(
-    FATAL_ERROR "Set either WITH_ABI_VERSION_1 or WITH_ABI_VERSION_2, not both")
-endif()
-
-if(WITH_ABI_VERSION_2)
-  set(OPENTELEMETRY_ABI_VERSION_NO "2")
-elseif(WITH_ABI_VERSION_1)
-  set(OPENTELEMETRY_ABI_VERSION_NO "1")
+if(OPENTELEMETRY_CPP_HEADER_VERSION_H MATCHES
+   "OPENTELEMETRY_ABI_VERSION_NO[ \t\r\n]+\"?([0-9]+)\"?")
+  math(EXPR OPENTELEMETRY_ABI_VERSION_NO ${CMAKE_MATCH_1})
 else()
-  if(OPENTELEMETRY_CPP_HEADER_VERSION_H MATCHES
-     "OPENTELEMETRY_ABI_VERSION_NO[ \t\r\n]+\"?([0-9]+)\"?")
-    math(EXPR OPENTELEMETRY_ABI_VERSION_NO ${CMAKE_MATCH_1})
-  else()
-    message(
-      FATAL_ERROR
-        "OPENTELEMETRY_ABI_VERSION_NO not found on ${CMAKE_CURRENT_LIST_DIR}/api/include/opentelemetry/version.h"
-    )
-  endif()
+  message(
+    FATAL_ERROR
+      "OPENTELEMETRY_ABI_VERSION_NO not found on ${CMAKE_CURRENT_LIST_DIR}/api/include/opentelemetry/version.h"
+  )
 endif()
-
-message(STATUS "OPENTELEMETRY_ABI_VERSION_NO=${OPENTELEMETRY_ABI_VERSION_NO}")
-
 if(OPENTELEMETRY_CPP_HEADER_VERSION_H MATCHES
   "OPENTELEMETRY_VERSION[ \t\r\n]+\"?([^\"]+)\"?")
  set(OPENTELEMETRY_VERSION ${CMAKE_MATCH_1})
@ -132,31 +102,55 @@ else()
  )
 endif()

-message(STATUS "OPENTELEMETRY_VERSION=${OPENTELEMETRY_VERSION}")
+option(WITH_STL "Whether to use Standard Library for C++latest features" OFF)

-option(WITH_NO_DEPRECATED_CODE "Do not include deprecated code" OFF)
+option(WITH_ABSEIL "Whether to use Abseil for C++latest features" OFF)

-set(WITH_STL
-    "OFF"
-    CACHE STRING "Which version of the Standard Library for C++ to use")
-
-option(WITH_GSL
-       "Whether to use Guidelines Support Library for C++ latest features" OFF)
-
-set(OPENTELEMETRY_INSTALL_default ON)
-if(NOT CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
-  set(OPENTELEMETRY_INSTALL_default OFF)
+if(NOT DEFINED CMAKE_CXX_STANDARD)
+  if(WITH_STL)
+    # Require at least C++17. C++20 is needed to avoid gsl::span
+    if(CMAKE_VERSION VERSION_GREATER 3.11.999)
+      # Ask for 20, may get anything below
+      set(CMAKE_CXX_STANDARD 20)
+    else()
+      # Ask for 17, may get anything below
+      set(CMAKE_CXX_STANDARD 17)
+    endif()
+  else()
+    set(CMAKE_CXX_STANDARD 11)
+  endif()
 endif()
-option(OPENTELEMETRY_INSTALL "Whether to install opentelemetry targets"
-       ${OPENTELEMETRY_INSTALL_default})

-include("${opentelemetry-cpp_SOURCE_DIR}/cmake/tools.cmake")
+if(WITH_ABSEIL)
+  find_package(absl CONFIG REQUIRED)

-if(NOT WITH_STL STREQUAL "OFF")
+  set(CORE_RUNTIME_LIBS absl::bad_variant_access absl::any absl::base
+                        absl::bits absl::city)
+
+  # target_link_libraries(main PRIVATE absl::any absl::base absl::bits
+  # absl::city)
+endif()
+
+if(WITH_STL)
  # These definitions are needed for test projects that do not link against
  # opentelemetry-api library directly. We ensure that variant implementation
  # (absl::variant or std::variant) in variant unit test code is consistent with
-  # the global project build definitions. Optimize for speed to reduce the hops
+  # the global project build definitions.
+  add_definitions(-DHAVE_CPP_STDLIB)
+  add_definitions(-DHAVE_GSL)
+
+  # Guidelines Support Library path. Used if we are not on not get C++20.
+  #
+  # TODO: respect WITH_ABSEIL as alternate implementation of std::span
+  find_package(Microsoft.GSL QUIET)
+  if(TARGET Microsoft.GSL::GSL)
+    list(APPEND CORE_RUNTIME_LIBS Microsoft.GSL::GSL)
+  else()
+    set(GSL_DIR third_party/ms-gsl)
+    include_directories(${GSL_DIR}/include)
+  endif()
+
+  # Optimize for speed to reduce the hops
  if(CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
    if(CMAKE_BUILD_TYPE MATCHES Debug)
      # Turn off optimizations for DEBUG
@ -171,32 +165,7 @@ if(NOT WITH_STL STREQUAL "OFF")
  endif()
 endif()

-option(WITH_OTLP_RETRY_PREVIEW
-       "Whether to enable experimental retry functionality" OFF)
-
-option(WITH_OTLP_GRPC_SSL_MTLS_PREVIEW
-       "Whether to enable mTLS support for gRPC" OFF)
-
-option(WITH_OTLP_GRPC_CREDENTIAL_PREVIEW
-       "Whether to enable gRPC credentials option in OTLP gRPC Exporter" OFF)
-
-option(WITH_OTLP_GRPC "Whether to include the OTLP gRPC exporter in the SDK"
-       OFF)
-
-option(WITH_OTLP_HTTP "Whether to include the OTLP http exporter in the SDK"
-       OFF)
-
-option(WITH_OTLP_FILE "Whether to include the OTLP file exporter in the SDK"
-       OFF)
-
-option(
-  WITH_OTLP_HTTP_COMPRESSION
-  "Whether to include gzip compression for the OTLP http exporter in the SDK"
-  OFF)
-
-option(WITH_CURL_LOGGING "Whether to enable select CURL verbosity in OTel logs"
-       OFF)
-
+option(WITH_OTLP "Whether to include the OpenTelemetry Protocol in the SDK" OFF)
 option(WITH_ZIPKIN "Whether to include the Zipkin exporter in the SDK" OFF)

 option(WITH_PROMETHEUS "Whether to include the Prometheus Client in the SDK"
@ -205,93 +174,79 @@ option(WITH_PROMETHEUS "Whether to include the Prometheus Client in the SDK"
 option(WITH_ELASTICSEARCH
       "Whether to include the Elasticsearch Client in the SDK" OFF)

+option(WITH_ZPAGES "Whether to include the Zpages Server in the SDK" OFF)
+
+option(WITH_JAEGER "Whether to include the Jaeger exporter" OFF)
+
 option(WITH_NO_GETENV "Whether the platform supports environment variables" OFF)

 option(BUILD_TESTING "Whether to enable tests" ON)

-option(WITH_BENCHMARK "Whether to build benchmark program" ON)
-
 option(BUILD_W3CTRACECONTEXT_TEST "Whether to build w3c trace context" OFF)

-option(OTELCPP_MAINTAINER_MODE "Build in maintainer mode (-Wall -Werror)" OFF)
-
-option(WITH_OPENTRACING "Whether to include the Opentracing shim" OFF)
-
-option(OTELCPP_VERSIONED_LIBS "Whether to generate the versioned shared libs"
-       OFF)
-
-if(OTELCPP_VERSIONED_LIBS AND NOT BUILD_SHARED_LIBS)
-  message(FATAL_ERROR "OTELCPP_VERSIONED_LIBS=ON requires BUILD_SHARED_LIBS=ON")
+if(WITH_NO_GENENV)
+  add_definitions(-DNO_GETENV)
 endif()

 if(WIN32)
-  option(WITH_ETW "Whether to include the ETW Exporter in the SDK" ON)
-else()
-  if(DEFINED (WITH_ETW))
-    message(FATAL_ERROR "WITH_ETW is only supported on Windows")
+  add_definitions(-DNOMINMAX)
+  if(BUILD_TESTING)
+    if(MSVC)
+      # GTest bug: https://github.com/google/googletest/issues/860
+      add_compile_options(/wd4275)
+    endif()
  endif()
+  option(WITH_ETW "Whether to include the ETW Exporter in the SDK" ON)
+  if(WITH_ETW)
+    add_definitions(-DHAVE_MSGPACK)
+  endif(WITH_ETW)
 endif(WIN32)

-# Do not convert deprecated message to error
-if(CMAKE_CXX_COMPILER_ID MATCHES "GNU|Clang|AppleClang")
-  add_compile_options(-Wno-error=deprecated-declarations)
-endif()
-
 option(
  WITH_API_ONLY
-  "Only build the API (use as a header-only library). Overrides WITH_EXAMPLES and all options to enable exporters"
+  "Only build the API (use as a header-only library). Overrides WITH_EXAMPLES"
  OFF)
 option(WITH_EXAMPLES "Whether to build examples" ON)

-# This requires CURL, OFF by default.
-option(
-  WITH_EXAMPLES_HTTP
-  "Whether to build http client/server examples. Requires WITH_EXAMPLES and CURL"
-  OFF)
+option(WITH_METRICS_PREVIEW "Whether to build metrics preview" OFF)

-option(WITH_FUNC_TESTS "Whether to build functional tests" ON)
-
-option(WITH_ASYNC_EXPORT_PREVIEW "Whether to enable async export" OFF)
-
-# Exemplar specs status is experimental, so behind feature flag by default
-option(WITH_METRICS_EXEMPLAR_PREVIEW
-       "Whether to enable exemplar within metrics" OFF)
-
-# Experimental, so behind feature flag by default
-option(WITH_THREAD_INSTRUMENTATION_PREVIEW
-       "Whether to enable thread instrumentation" OFF)
-
-option(WITH_RESOURCE_DETECTORS_PREVIEW
-       "Whether to enable inbuilt resource detectors" OFF)
-
-option(OPENTELEMETRY_SKIP_DYNAMIC_LOADING_TESTS
-       "Whether to build test libraries that are always linked as shared libs"
-       OFF)
-
-#
-# Verify options dependencies
-#
-
-include(FetchContent)
-
-if(WITH_EXAMPLES_HTTP AND NOT WITH_EXAMPLES)
-  message(FATAL_ERROR "WITH_EXAMPLES_HTTP=ON requires WITH_EXAMPLES=ON")
+if(WITH_METRICS_PREVIEW)
+  add_definitions(-DENABLE_METRICS_PREVIEW)
 endif()

-if(WITH_GSL)
-  include("${opentelemetry-cpp_SOURCE_DIR}/cmake/ms-gsl.cmake")
+option(WITH_LOGS_PREVIEW "Whether to build logs preview" OFF)
+
+if(WITH_LOGS_PREVIEW)
+  add_definitions(-DENABLE_LOGS_PREVIEW)
 endif()

 find_package(Threads)

-function(set_target_version target_name)
-  if(OTELCPP_VERSIONED_LIBS)
-    set_target_properties(
-      ${target_name} PROPERTIES VERSION ${OPENTELEMETRY_VERSION}
-                                SOVERSION ${OPENTELEMETRY_ABI_VERSION_NO})
-  endif()
+function(install_windows_deps)
+  # Bootstrap vcpkg from CMake and auto-install deps in case if we are missing
+  # deps on Windows. Respect the target architecture variable.
+  set(VCPKG_TARGET_ARCHITECTURE
+      ${ARCH}
+      PARENT_SCOPE)
+  message("Installing build tools and dependencies...")
+  set(ENV{ARCH} ${ARCH})
+  execute_process(
+    COMMAND ${CMAKE_CURRENT_SOURCE_DIR}/tools/setup-buildtools.cmd)
+  set(CMAKE_TOOLCHAIN_FILE
+      ${CMAKE_CURRENT_SOURCE_DIR}/tools/vcpkg/scripts/buildsystems/vcpkg.cmake
+      PARENT_SCOPE)
 endfunction()

+if(WITH_JAEGER)
+  find_package(Thrift QUIET)
+  if(NOT Thrift_FOUND)
+    # Install Thrift and propagate via vcpkg toolchain file
+    if(WIN32 AND (NOT DEFINED CMAKE_TOOLCHAIN_FILE))
+      install_windows_deps()
+    endif()
+  endif()
+endif()
+
 if(MSVC)
  # Options for Visual C++ compiler: /Zc:__cplusplus - report an updated value
  # for recent C++ language standards. Without this option MSVC returns the
@ -300,6 +255,12 @@ if(MSVC)
    # __cplusplus flag is not supported by Visual Studio 2015
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /Zc:__cplusplus")
  endif()
+  # When using vcpkg, all targets build with the same runtime
+  if(VCPKG_TOOLCHAIN)
+    set(CMAKE_MSVC_RUNTIME_LIBRARY
+        "MultiThreaded$<$<CONFIG:Debug>:Debug>$<$<STREQUAL:${VCPKG_CRT_LINKAGE},dynamic>:DLL>"
+        CACHE STRING "")
+  endif()
 endif()

 # include GNUInstallDirs before include cmake/opentelemetry-proto.cmake because
@ -307,379 +268,192 @@ endif()
 # GNUInstallDirs.
 include(GNUInstallDirs)

-#
-# Do we need HTTP CLIENT CURL ?
-#
-
-if(WITH_OTLP_HTTP
+if((NOT WITH_API_ONLY)
   OR WITH_ELASTICSEARCH
   OR WITH_ZIPKIN
-   OR BUILD_W3CTRACECONTEXT_TEST
-   OR WITH_EXAMPLES_HTTP)
-  set(WITH_HTTP_CLIENT_CURL ON)
-else()
-  set(WITH_HTTP_CLIENT_CURL OFF)
-endif()
-
-#
-# Do we need ZLIB ?
-#
-
-if((NOT WITH_API_ONLY)
-   AND WITH_HTTP_CLIENT_CURL
-   AND WITH_OTLP_HTTP_COMPRESSION)
-  include("${opentelemetry-cpp_SOURCE_DIR}/cmake/zlib.cmake")
-endif()
-
-#
-# Do we need CURL ?
-#
-
-if((NOT WITH_API_ONLY) AND WITH_HTTP_CLIENT_CURL)
-  include("${opentelemetry-cpp_SOURCE_DIR}/cmake/curl.cmake")
-endif()
-
-#
-# Do we need prometheus-cpp ?
-#
-
-if(WITH_PROMETHEUS)
-  include("${opentelemetry-cpp_SOURCE_DIR}/cmake/prometheus-cpp.cmake")
-endif()
-
-#
-# Do we need protobuf and/or gRPC ?
-#
-
-if(WITH_OTLP_GRPC
+   OR WITH_OTLP
   OR WITH_OTLP_HTTP
-   OR WITH_OTLP_FILE)
-
-  # find or fetch grpc before protobuf to allow protobuf to be built in-tree as
-  # a grpc submodule.
-  if(WITH_OTLP_GRPC)
-    include("${opentelemetry-cpp_SOURCE_DIR}/cmake/grpc.cmake")
-  endif()
-
-  include("${opentelemetry-cpp_SOURCE_DIR}/cmake/protobuf.cmake")
-
-  include("${opentelemetry-cpp_SOURCE_DIR}/cmake/opentelemetry-proto.cmake")
-endif()
-
-#
-# Do we need NLOHMANN_JSON ?
-#
-
-if(WITH_ELASTICSEARCH
-   OR WITH_ZIPKIN
-   OR WITH_OTLP_HTTP
-   OR WITH_OTLP_FILE
+   OR WITH_ZPAGES
   OR BUILD_W3CTRACECONTEXT_TEST
   OR WITH_ETW)
-  set(USE_NLOHMANN_JSON ON)
-else()
-  set(USE_NLOHMANN_JSON OFF)
-endif()
-
-if((NOT WITH_API_ONLY) AND USE_NLOHMANN_JSON)
-  include("${opentelemetry-cpp_SOURCE_DIR}/cmake/nlohmann-json.cmake")
-endif()
-
-#
-# Do we need OpenTracing ?
-#
-
-if(WITH_OPENTRACING)
-  include("${opentelemetry-cpp_SOURCE_DIR}/cmake/opentracing-cpp.cmake")
-endif()
-
-if(OTELCPP_MAINTAINER_MODE)
-  if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
-    message(STATUS "Building with gcc in maintainer mode.")
-
-    add_compile_options(-Wall)
-    add_compile_options(-Werror)
-    add_compile_options(-Wextra)
-
-    # Tested with GCC 9.4 on github.
-    if(CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 9.4)
-      message(STATUS "Building with additional warnings for gcc.")
-
-      # Relaxed warnings
-
-      # Enforced warnings
-
-      # C++ options only
-      add_compile_options($<$<STREQUAL:$<COMPILE_LANGUAGE>,CXX>:-Wextra-semi>)
-      add_compile_options(
-        $<$<STREQUAL:$<COMPILE_LANGUAGE>,CXX>:-Woverloaded-virtual>)
-      add_compile_options(
-        $<$<STREQUAL:$<COMPILE_LANGUAGE>,CXX>:-Wsuggest-override>)
-      add_compile_options(
-        $<$<STREQUAL:$<COMPILE_LANGUAGE>,CXX>:-Wold-style-cast>)
-
-      # C and C++
-      add_compile_options(-Wcast-qual)
-      add_compile_options(-Wformat-security)
-      add_compile_options(-Wlogical-op)
-      add_compile_options(-Wmissing-include-dirs)
-      add_compile_options(-Wstringop-truncation)
-      add_compile_options(-Wundef)
-      add_compile_options(-Wvla)
-    endif()
-  elseif(CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
-    message(STATUS "Building with clang in maintainer mode.")
-
-    add_compile_options(-Wall)
-    add_compile_options(-Werror)
-    add_compile_options(-Wextra)
-
-    # Tested with Clang 11.0 on github.
-    if(CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 11.0)
-      message(STATUS "Building with additional warnings for clang.")
-
-      # Relaxed warnings
-      add_compile_options(-Wno-error=unused-private-field)
-
-      # Enforced warnings
-      add_compile_options(-Wcast-qual)
-      add_compile_options(-Wconditional-uninitialized)
-      add_compile_options(-Wextra-semi)
-      add_compile_options(-Wformat-security)
-      add_compile_options(-Wheader-hygiene)
-      add_compile_options(-Winconsistent-missing-destructor-override)
-      add_compile_options(-Winconsistent-missing-override)
-      add_compile_options(-Wnewline-eof)
-      add_compile_options(-Wnon-virtual-dtor)
-      add_compile_options(-Woverloaded-virtual)
-      add_compile_options(-Wrange-loop-analysis)
-      add_compile_options(-Wundef)
-      add_compile_options(-Wundefined-reinterpret-cast)
-      add_compile_options(-Wvla)
-      add_compile_options(-Wold-style-cast)
-    endif()
-  elseif(CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
-    message(STATUS "Building with msvc in maintainer mode.")
-
-    add_compile_options(/WX)
-    add_compile_options(/W4)
-
-    # Relaxed warnings
-    add_compile_options(/wd4100)
-    add_compile_options(/wd4125)
-    add_compile_options(/wd4566)
-    add_compile_options(/wd4127)
-    add_compile_options(/wd4512)
-    add_compile_options(/wd4267)
-    add_compile_options(/wd4996)
-
-    # Enforced warnings
-    add_compile_options(/we4265) # 'class': class has virtual functions, but
-                                 # destructor is not virtual
-    add_compile_options(/we5204) # A class with virtual functions has
-                                 # non-virtual trivial destructor.
-
-  elseif()
-    message(FATAL_ERROR "Building with unknown compiler in maintainer mode.")
+  # nlohmann_json package is required for most SDK build configurations
+  find_package(nlohmann_json QUIET)
+  set(nlohmann_json_clone FALSE)
+  if(nlohmann_json_FOUND)
+    message("Using external nlohmann::json")
+  elseif(EXISTS ${PROJECT_SOURCE_DIR}/.git
+         AND EXISTS
+             ${PROJECT_SOURCE_DIR}/third_party/nlohmann-json/CMakeLists.txt)
+    message("Trying to use local nlohmann::json from submodule")
+    set(JSON_BuildTests
+        OFF
+        CACHE INTERNAL "")
+    set(JSON_Install
+        ON
+        CACHE INTERNAL "")
+    # This option allows to link nlohmann_json::nlohmann_json target
+    add_subdirectory(${PROJECT_SOURCE_DIR}/third_party/nlohmann-json)
+    # This option allows to add header to include directories
+    include_directories(
+      ${PROJECT_SOURCE_DIR}/third_party/nlohmann-json/single_include)
+  else()
+    set(nlohmann_json_clone TRUE)
+    include(cmake/nlohmann-json.cmake)
+    message("\nnlohmann_json package was not found. Cloning from github")
  endif()
-endif(OTELCPP_MAINTAINER_MODE)
+endif()
+
+if(WITH_PROMETHEUS)
+  find_package(prometheus-cpp CONFIG QUIET)
+  if(NOT prometheus-cpp_FOUND)
+    message("Trying to use local prometheus-cpp from submodule")
+    if(EXISTS ${PROJECT_SOURCE_DIR}/third_party/prometheus-cpp/.git)
+      add_subdirectory(third_party/prometheus-cpp)
+    else()
+      message(
+        FATAL_ERROR
+          "\nprometheus-cpp package was not found. Please either provide it manually or clone with submodules. "
+          "To initialize, fetch and checkout any nested submodules, you can use the following command:\n"
+          "git submodule update --init --recursive")
+    endif()
+  else()
+    message("Using external prometheus-cpp")
+  endif()
+endif()
+
+if(WITH_OTLP)
+  set(protobuf_MODULE_COMPATIBLE ON)
+  find_package(Protobuf)
+  if(WITH_OTLP_GRPC)
+    find_package(gRPC)
+  endif()
+  if((NOT Protobuf_FOUND AND NOT PROTOBUF_FOUND) OR (NOT gRPC_FOUND))
+    if(WIN32 AND (NOT DEFINED CMAKE_TOOLCHAIN_FILE))
+      install_windows_deps()
+    endif()
+
+    if(WIN32 AND (NOT DEFINED CMAKE_TOOLCHAIN_FILE))
+      message(STATUS_FATAL "Windows dependency installation failed!")
+    endif()
+    if(WIN32)
+      include(${CMAKE_TOOLCHAIN_FILE})
+    endif()
+
+    if(NOT Protobuf_FOUND AND NOT PROTOBUF_FOUND)
+      find_package(Protobuf REQUIRED)
+    endif()
+    if(WITH_OTLP_GRPC AND NOT gRPC_FOUND)
+      find_package(gRPC)
+    endif()
+    if(WIN32)
+      # Always use x64 protoc.exe
+      if(NOT EXISTS "${Protobuf_PROTOC_EXECUTABLE}")
+        set(Protobuf_PROTOC_EXECUTABLE
+            ${CMAKE_CURRENT_SOURCE_DIR}/tools/vcpkg/packages/protobuf_x64-windows/tools/protobuf/protoc.exe
+        )
+      endif()
+    endif()
+    # Latest Protobuf uses mixed case instead of uppercase
+    if(Protobuf_PROTOC_EXECUTABLE)
+      set(PROTOBUF_PROTOC_EXECUTABLE ${Protobuf_PROTOC_EXECUTABLE})
+    endif()
+  endif()
+  message("PROTOBUF_PROTOC_EXECUTABLE=${PROTOBUF_PROTOC_EXECUTABLE}")
+
+  include(cmake/opentelemetry-proto.cmake)
+  include(CMakeDependentOption)
+  find_package(CURL)
+
+  cmake_dependent_option(
+    WITH_OTLP_GRPC "Whether to include the OTLP gRPC exporter in the SDK" ON
+    "gRPC_FOUND" OFF)
+  cmake_dependent_option(
+    WITH_OTLP_HTTP "Whether to include the OTLP http exporter in the SDK" ON
+    "CURL_FOUND" OFF)
+endif()

 list(APPEND CMAKE_PREFIX_PATH "${CMAKE_BINARY_DIR}")

 include(CTest)
 if(BUILD_TESTING)
-  include("${opentelemetry-cpp_SOURCE_DIR}/cmake/googletest.cmake")
-  enable_testing()
-  if(WITH_BENCHMARK)
-    include("${opentelemetry-cpp_SOURCE_DIR}/cmake/benchmark.cmake")
+  if(EXISTS ${CMAKE_BINARY_DIR}/lib/libgtest.a)
+    # Prefer GTest from build tree. GTest is not always working with
+    # CMAKE_PREFIX_PATH
+    set(GTEST_INCLUDE_DIRS
+        ${CMAKE_CURRENT_SOURCE_DIR}/third_party/googletest/googletest/include
+        ${CMAKE_CURRENT_SOURCE_DIR}/third_party/googletest/googlemock/include)
+    set(GTEST_BOTH_LIBRARIES
+        ${CMAKE_BINARY_DIR}/lib/libgtest.a
+        ${CMAKE_BINARY_DIR}/lib/libgtest_main.a
+        ${CMAKE_BINARY_DIR}/lib/libgmock.a)
+  elseif(WIN32)
+    # Make sure we are always bootsrapped with vcpkg on Windows
+    find_package(GTest)
+    if(NOT (GTEST_FOUND OR GTest_FOUND))
+      install_windows_deps()
+      find_package(GTest REQUIRED)
+    endif()
+  else()
+    # Prefer GTest installed by OS distro, brew or vcpkg package manager
+    find_package(GTest REQUIRED)
  endif()
+  include_directories(SYSTEM ${GTEST_INCLUDE_DIRS})
+  message("GTEST_INCLUDE_DIRS   = ${GTEST_INCLUDE_DIRS}")
+  message("GTEST_BOTH_LIBRARIES = ${GTEST_BOTH_LIBRARIES}")
+  enable_testing()
+  # Benchmark respects the CMAKE_PREFIX_PATH
+  find_package(benchmark CONFIG REQUIRED)
 endif()

-# Record build config and versions
-message(STATUS "---------------------------------------------")
-message(STATUS "build settings")
-message(STATUS "---------------------------------------------")
-message(STATUS "OpenTelemetry: ${OPENTELEMETRY_VERSION}")
-message(STATUS "OpenTelemetry ABI: ${OPENTELEMETRY_ABI_VERSION_NO}")
-message(STATUS "CMAKE_SYSTEM_PROCESSOR: ${CMAKE_SYSTEM_PROCESSOR}")
-message(STATUS "CXX: ${CMAKE_CXX_COMPILER_ID} ${CMAKE_CXX_COMPILER_VERSION}")
-message(STATUS "CMAKE_BUILD_TYPE: ${CMAKE_BUILD_TYPE}")
-message(STATUS "CXXFLAGS: ${CMAKE_CXX_FLAGS}")
-message(STATUS "CMAKE_CXX_STANDARD: ${CMAKE_CXX_STANDARD}")
-message(STATUS "CMAKE_TOOLCHAIN_FILE: ${CMAKE_TOOLCHAIN_FILE}")
-message(STATUS "BUILD_SHARED_LIBS: ${BUILD_SHARED_LIBS}")
-
-message(STATUS "---------------------------------------------")
-message(STATUS "opentelemetry-cpp build options")
-message(STATUS "---------------------------------------------")
-message(STATUS "WITH_API_ONLY: ${WITH_API_ONLY}")
-message(STATUS "WITH_NO_DEPRECATED_CODE: ${WITH_NO_DEPRECATED_CODE}")
-message(STATUS "WITH_ABI_VERSION_1: ${WITH_ABI_VERSION_1}")
-message(STATUS "WITH_ABI_VERSION_2: ${WITH_ABI_VERSION_2}")
-message(STATUS "OTELCPP_VERSIONED_LIBS: ${OTELCPP_VERSIONED_LIBS}")
-message(STATUS "OTELCPP_MAINTAINER_MODE: ${OTELCPP_MAINTAINER_MODE}")
-message(STATUS "WITH_STL: ${WITH_STL}")
-message(STATUS "WITH_GSL: ${WITH_GSL}")
-message(STATUS "WITH_NO_GETENV: ${WITH_NO_GETENV}")
-
-message(STATUS "---------------------------------------------")
-message(STATUS "opentelemetry-cpp cmake component options")
-message(STATUS "---------------------------------------------")
-message(STATUS "WITH_OTLP_GRPC: ${WITH_OTLP_GRPC}")
-message(STATUS "WITH_OTLP_HTTP: ${WITH_OTLP_HTTP}")
-message(STATUS "WITH_OTLP_FILE: ${WITH_OTLP_FILE}")
-message(STATUS "WITH_HTTP_CLIENT_CURL: ${WITH_HTTP_CLIENT_CURL}")
-message(STATUS "WITH_ZIPKIN: ${WITH_ZIPKIN}")
-message(STATUS "WITH_PROMETHEUS: ${WITH_PROMETHEUS}")
-message(STATUS "WITH_ELASTICSEARCH: ${WITH_ELASTICSEARCH}")
-message(STATUS "WITH_OPENTRACING: ${WITH_OPENTRACING}")
-message(STATUS "WITH_ETW: ${WITH_ETW}")
-message(STATUS "OPENTELEMETRY_BUILD_DLL: ${OPENTELEMETRY_BUILD_DLL}")
-
-message(STATUS "---------------------------------------------")
-message(STATUS "feature preview options")
-message(STATUS "---------------------------------------------")
-message(STATUS "WITH_ASYNC_EXPORT_PREVIEW: ${WITH_ASYNC_EXPORT_PREVIEW}")
-message(
-  STATUS
-    "WITH_THREAD_INSTRUMENTATION_PREVIEW: ${WITH_THREAD_INSTRUMENTATION_PREVIEW}"
-)
-message(
-  STATUS "WITH_METRICS_EXEMPLAR_PREVIEW: ${WITH_METRICS_EXEMPLAR_PREVIEW}")
-message(
-  STATUS "WITH_OTLP_GRPC_SSL_MTLS_PREVIEW: ${WITH_OTLP_GRPC_SSL_MTLS_PREVIEW}")
-message(
-  STATUS
-    "WITH_OTLP_GRPC_CREDENTIAL_PREVIEW: ${WITH_OTLP_GRPC_CREDENTIAL_PREVIEW}")
-message(STATUS "WITH_OTLP_RETRY_PREVIEW: ${WITH_OTLP_RETRY_PREVIEW}")
-message(STATUS "---------------------------------------------")
-message(STATUS "third-party options")
-message(STATUS "---------------------------------------------")
-message(STATUS "WITH_NLOHMANN_JSON: ${USE_NLOHMANN_JSON}")
-message(STATUS "WITH_CURL_LOGGING: ${WITH_CURL_LOGGING}")
-message(STATUS "WITH_OTLP_HTTP_COMPRESSION: ${WITH_OTLP_HTTP_COMPRESSION}")
-message(STATUS "---------------------------------------------")
-message(STATUS "examples and test options")
-message(STATUS "---------------------------------------------")
-message(STATUS "WITH_BENCHMARK: ${WITH_BENCHMARK}")
-message(STATUS "WITH_EXAMPLES: ${WITH_EXAMPLES}")
-message(STATUS "WITH_EXAMPLES_HTTP: ${WITH_EXAMPLES_HTTP}")
-message(STATUS "WITH_FUNC_TESTS: ${WITH_FUNC_TESTS}")
-message(STATUS "BUILD_W3CTRACECONTEXT_TEST: ${BUILD_W3CTRACECONTEXT_TEST}")
-message(STATUS "BUILD_TESTING: ${BUILD_TESTING}")
-message(STATUS "---------------------------------------------")
-message(STATUS "versions")
-message(STATUS "---------------------------------------------")
-message(STATUS "CMake: ${CMAKE_VERSION}")
-message(STATUS "GTest: ${GTest_VERSION} (${GTest_PROVIDER})")
-message(STATUS "benchmark: ${benchmark_VERSION} (${benchmark_PROVIDER})")
-if(WITH_GSL)
-  message(
-    STATUS "Microsoft.GSL: ${Microsoft.GSL_VERSION} (${Microsoft.GSL_PROVIDER})"
-  )
-endif()
-if(absl_FOUND)
-  message(STATUS "Abseil: ${absl_VERSION}")
-endif()
-if(opentelemetry-proto_VERSION)
-  message(
-    STATUS
-      "opentelemetry-proto: ${opentelemetry-proto_VERSION} (${opentelemetry-proto_PROVIDER})"
-  )
-endif()
-if(Protobuf_VERSION)
-  message(
-    STATUS
-      "Protobuf: ${Protobuf_VERSION} (${Protobuf_PROVIDER} - ${protobuf_lib_type})"
-  )
-endif()
-if(gRPC_VERSION)
-  message(STATUS "gRPC: ${gRPC_VERSION} (${gRPC_PROVIDER} - ${grpc_lib_type})")
-endif()
-if(CURL_VERSION)
-  message(STATUS "CURL: ${CURL_VERSION} (${CURL_PROVIDER})")
-endif()
-if(ZLIB_VERSION)
-  message(STATUS "ZLIB: ${ZLIB_VERSION} (${ZLIB_PROVIDER})")
-endif()
-if(USE_NLOHMANN_JSON)
-  message(
-    STATUS "nlohmann-json: ${nlohmann_json_VERSION} (${nlohmann_json_PROVIDER})"
-  )
-endif()
-if(WITH_PROMETHEUS)
-  message(
-    STATUS
-      "prometheus-cpp: ${prometheus-cpp_VERSION} (${prometheus-cpp_PROVIDER})")
-endif()
-if(WITH_OPENTRACING)
-  message(
-    STATUS "opentracing-cpp: ${OpenTracing_VERSION} (${OpenTracing_PROVIDER})")
-endif()
-message(STATUS "---------------------------------------------")
-
-include("${opentelemetry-cpp_SOURCE_DIR}/cmake/otel-install-functions.cmake")
-
 include(CMakePackageConfigHelpers)

-if(DEFINED OPENTELEMETRY_BUILD_DLL)
-  if(NOT WIN32)
-    message(FATAL_ERROR "Build DLL is only supported on Windows!")
-  endif()
-  if(NOT MSVC)
-    message(WARNING "Build DLL is supposed to work with MSVC!")
-  endif()
-  if(WITH_STL)
-    message(
-      WARNING "Build DLL with C++ STL could cause binary incompatibility!")
-  endif()
-  add_definitions(-DOPENTELEMETRY_BUILD_EXPORT_DLL)
-endif()
+include_directories(api/include)

 add_subdirectory(api)

-if(WITH_OPENTRACING)
-  add_subdirectory(opentracing-shim)
-endif()
-
 if(NOT WITH_API_ONLY)
-  set(BUILD_TESTING ${BUILD_TESTING})
+  include_directories(sdk/include)
+  include_directories(sdk)
+  include_directories(ext/include)

  add_subdirectory(sdk)
  add_subdirectory(ext)
  add_subdirectory(exporters)
-  if(WITH_RESOURCE_DETECTORS_PREVIEW)
-    add_subdirectory(resource_detectors)
-  endif()
-
-  if(BUILD_TESTING)
-    add_subdirectory(test_common)
-  endif()
  if(WITH_EXAMPLES)
    add_subdirectory(examples)
  endif()
-  if(WITH_FUNC_TESTS)
-    add_subdirectory(functional)
-  endif()
 endif()

-include(
-  "${opentelemetry-cpp_SOURCE_DIR}/cmake/opentelemetry-build-external-component.cmake"
+# Export cmake config and support find_packages(opentelemetry-cpp CONFIG) Write
+# config file for find_packages(opentelemetry-cpp CONFIG)
+set(INCLUDE_INSTALL_DIR "${CMAKE_INSTALL_INCLUDEDIR}")
+configure_package_config_file(
+  "${CMAKE_CURRENT_LIST_DIR}/cmake/opentelemetry-cpp-config.cmake.in"
+  "${CMAKE_CURRENT_BINARY_DIR}/cmake/${PROJECT_NAME}/${PROJECT_NAME}-config.cmake"
+  INSTALL_DESTINATION "${CMAKE_INSTALL_LIBDIR}/cmake/${PROJECT_NAME}"
+  PATH_VARS OPENTELEMETRY_ABI_VERSION_NO OPENTELEMETRY_VERSION PROJECT_NAME
+            INCLUDE_INSTALL_DIR CMAKE_INSTALL_LIBDIR
+  NO_CHECK_REQUIRED_COMPONENTS_MACRO)
+
+# Write version file for find_packages(opentelemetry-cpp CONFIG)
+write_basic_package_version_file(
+  "${CMAKE_CURRENT_BINARY_DIR}/cmake/${PROJECT_NAME}/${PROJECT_NAME}-config-version.cmake"
+  VERSION ${OPENTELEMETRY_VERSION}
+  COMPATIBILITY ExactVersion)
+
+install(
+  FILES
+    "${CMAKE_CURRENT_BINARY_DIR}/cmake/${PROJECT_NAME}/${PROJECT_NAME}-config.cmake"
+    "${CMAKE_CURRENT_BINARY_DIR}/cmake/${PROJECT_NAME}/${PROJECT_NAME}-config-version.cmake"
+  DESTINATION "${CMAKE_INSTALL_LIBDIR}/cmake/${PROJECT_NAME}")
+
+# Export all components
+export(
+  EXPORT "${PROJECT_NAME}-target"
+  NAMESPACE "${PROJECT_NAME}::"
+  FILE "${CMAKE_CURRENT_BINARY_DIR}/cmake/${PROJECT_NAME}/${PROJECT_NAME}-target.cmake"
 )
-include("${opentelemetry-cpp_SOURCE_DIR}/cmake/patch-imported-config.cmake")
-
-if(OPENTELEMETRY_INSTALL)
-  # Install the cmake config and version files
-  otel_install_cmake_config()
-
-  # Install the components and associated files
-  otel_install_components()
-
-  # Install the thirdparty dependency definition file
-  otel_install_thirdparty_definitions()
-
-  if(BUILD_PACKAGE)
-    include("${opentelemetry-cpp_SOURCE_DIR}/cmake/package.cmake")
-    include(CPack)
-  endif()
-endif()
+install(
+  EXPORT "${PROJECT_NAME}-target"
+  NAMESPACE "${PROJECT_NAME}::"
+  DESTINATION "${CMAKE_INSTALL_LIBDIR}/cmake/${PROJECT_NAME}")
--- a/CMakeSettings.json
+++ b/CMakeSettings.json
@ -14,7 +14,7 @@
      "ctestCommandArgs": "",
      "variables": [
        {
-          "name": "WITH_OTLP_GRPC",
+          "name": "WITH_OTLP",
          "value": "True",
          "type": "BOOL"
        },
@ -40,7 +40,7 @@
      "cmakeToolchain": "",
      "variables": [
        {
-          "name": "WITH_OTLP_GRPC",
+          "name": "WITH_OTLP",
          "value": "True",
          "type": "BOOL"
        },
@ -70,7 +70,7 @@
          "type": "BOOL"
        },
        {
-          "name": "WITH_OTLP_GRPC",
+          "name": "WITH_OTLP",
          "value": "True",
          "type": "BOOL"
        },
@ -106,7 +106,7 @@
          "type": "BOOL"
        },
        {
-          "name": "WITH_OTLP_GRPC",
+          "name": "WITH_OTLP",
          "value": "True",
          "type": "BOOL"
        },
@ -123,4 +123,4 @@
      ]
    }
  ]
-}
+}
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@ -60,121 +60,6 @@ bazel build //examples/simple:example_simple
 bazel-bin/examples/simple/example_simple
 ```

-### DevContainer Setup for Project
-
-This guide provides instructions on how to set up and use the development
-container (`devcontainer`) environment to streamline testing and development
-for this project. With the DevContainer, you can work in a consistent environment
-configured with all the necessary dependencies and tools.
-
-#### Prerequisites
-
-Before getting started, ensure you have the following installed:
-
-* **Docker**: DevContainers require Docker for containerization.
-* **Visual Studio Code (VSCode)** with the **Remote - Containers** extension.
-
-#### Getting Started
-
-* **Open the Project in DevContainer**:
-
-   Open the project in VSCode. When prompted to "Reopen in Container," select
-   this option. If you’re not prompted, you can manually open the container by
-   selecting **Remote-Containers: Reopen in Container** from the command palette
-   (`F1` or `Ctrl+Shift+P`).
-
-* **Container Setup**:
-
-   The DevContainer environment will automatically build based on the configuration
-   files provided (e.g., `.devcontainer/devcontainer.json`). This setup will install
-   required dependencies, tools, and environment variables needed for the project.
-
-* **Container Customization**:
-   See `.devcontainer/README.md` for devcontainer configuration options.
-
-#### Available Commands
-
-Once inside the DevContainer, you can use the following commands to run tests
-and CI workflows.
-
-##### 1. Run Tests with Bazelisk
-
-To run tests with Bazelisk using specific compilation options, use:
-
-```bash
-bazelisk-linux-amd64 test --copt=-DENABLE_LOGS_PREVIEW
--test_output=errors --cache_test_results=no --copt=-DENABLE_TEST //exporters/otlp/...
-```
-
-###### Command Breakdown
-
-* `--copt=-DENABLE_LOGS_PREVIEW`: Enables preview logs.
-* `--test_output=errors`: Shows only the errors in the test output.
-* `--cache_test_results=no`: Forces Bazel to re-run tests without caching.
-* `--copt=-DENABLE_TEST`: Enables testing capabilities for the target code.
-* `//exporters/otlp/...`: Specifies the test target path.
-
-##### 2. Run CI Script
-
-You can also run the CI script provided to perform testing with the
-following command as an
-example:
-
-```bash
-bash ci/do_ci.sh cmake.exporter.otprotocol.test
-```
-
-This command initiates the CI pipeline, executing tests specifically for the
-**cmake.exporter.otprotocol** module.
-
-#### Troubleshooting
-
-If you encounter issues:
-
-* **Rebuild the DevContainer**: From the command palette, run
-  **Remote-Containers: Rebuild Container** to reinitialize the environment.
-* **Check Bazelisk and CI Script Logs**: Inspect logs for any configuration or
-  dependency issues.
-
-#### Additional Notes
-
-* You can adjust compiler options (`--copt`) as needed to test additional flags
-  or enable/disable specific features.
-* The test results will be displayed in the terminal within the DevContainer for
-  easy debugging.
-
-#### Resources
-
-* **Bazelisk Documentation**: [https://github.com/bazelbuild/bazelisk](https://github.com/bazelbuild/bazelisk)
-* **VSCode DevContainer Documentation**: [https://code.visualstudio.com/docs/remote/containers](https://code.visualstudio.com/docs/remote/containers)
-
-### Docker Development Image
-
-The `.devcontainer/Dockerfile.dev`
-dockerfile can be built directly with the following command.
-
-```sh
- docker build -t opentelemetry-cpp-dev -f ./.devcontainer/Dockerfile.dev .
-```
-
-You can customize the image using build arguments
- to match permissions with the host user.
-
-```sh
- docker build -t opentelemetry-cpp-dev \
-  --build-arg USER_UID="$(id -u)" \
-  --build-arg USER_GID="$(id -g)" \
-  -f ./.devcontainer/Dockerfile.dev .
-
-```
-
-Run an interactive bash session binding your host
- opentelemetry-cpp directory to the container's workspace:
-
-```sh
-docker run -it -v "$PWD:/workspaces/opentelemetry-cpp" opentelemetry-cpp-dev bash
-```
-
 ## Pull Requests

 ### How to Send Pull Requests
@ -202,12 +87,6 @@ git submodule init
 git submodule update
 ```

-The source code is automatically formatted using clang-format.
-
-The output can vary between versions, so make sure to install `clang-format`
-version `10.0`, and have `clang-format-10` in your execution path,
-so that the helper script `tools/format.sh` can find it.
-
 Check out a new branch, make modifications and push the branch to your fork:

 ```sh
@ -225,12 +104,6 @@ If you made changes to the Markdown documents (`*.md` files), install the latest
 markdownlint .
 ```

-If you modified shell scripts (`*.sh` files), install `shellcheck` and run:
-
-```sh
-shellcheck --severity=error <path to shell script>.sh
-```
-
 Open a pull request against the main `opentelemetry-cpp` repo.

 To run tests locally, please read the [CI instructions](ci/README.md).
@ -307,11 +180,11 @@ the C++ repository.

 * [OpenTelemetry
  Specification](https://github.com/open-telemetry/opentelemetry-specification)
-* The OpenTelemetry Specification describes the requirements and expectations
-  of for all OpenTelemetry implementations.
+  * The OpenTelemetry Specification describes the requirements and expectations
+    of for all OpenTelemetry implementations.

 * Read through the OpenTelemetry C++ documentation
-* The
+  * The
    [API](https://opentelemetry-cpp.readthedocs.io/en/latest/api/api.html)
    and
    [SDK](https://opentelemetry-cpp.readthedocs.io/en/latest/sdk/sdk.html)
--- a/DEPRECATED.md
+++ b/DEPRECATED.md
@ -1,65 +0,0 @@
-# Deprecated
-
-This document lists all the items currently deprecated in opentelemetry-cpp.
-
-Deprecated items will be removed in the future.
-
-## Guidelines
-
-### Maintainer guidelines
-
-See the [deprecation-process](./docs/deprecation-process.md)
-
-## [TEMPLATE]
-
-### New Deprecation Title (Template)
-
-#### Announcement (Template)
-
-#### Motivation (Template)
-
-#### Scope (Template)
-
-#### Mitigation (Template)
-
-#### Planned removal (Template)
-
-## [Platforms]
-
-N/A
-
-## [Compilers]
-
-N/A
-
-## [Third party dependencies]
-
-N/A
-
-## [Build tools]
-
-N/A
-
-## [Build scripts]
-
-N/A
-
-## [opentelemetry-cpp API]
-
-N/A
-
-## [opentelemetry-cpp SDK]
-
-N/A
-
-## [opentelemetry-cpp Exporter]
-
-N/A
-
-## [Documentation]
-
-N/A
-
-## Semantic conventions
-
-N/A
--- a/INSTALL.md
+++ b/INSTALL.md
@ -5,74 +5,47 @@ build systems for opentelemetry-cpp.

 ## Dependencies

-You can link OpenTelemetry C++ SDK with libraries provided in
-[dependencies.md](https://github.com/open-telemetry/opentelemetry-cpp/blob/main/docs/dependencies.md)
-(complete list of libraries with versions used in our CI can be found
-[here](https://github.com/open-telemetry/opentelemetry-cpp/blob/main/third_party_release)).
+You can link OpenTelemetry C++ SDK with libraries provided in [dependencies.md](https://github.com/open-telemetry/opentelemetry-cpp/blob/main/docs/dependencies.md) (complete list of libraries with versions used in our CI can be found [here](https://github.com/open-telemetry/opentelemetry-cpp/blob/main/third_party_release)).

 ## Build instructions using CMake

-### Prerequisites for CMake build
+### Prerequisites for CMake

 - A supported platform (e.g. Windows, macOS or Linux). Refer to [Platforms
  Supported](./README.md#supported-development-platforms) for more information.
- A compatible C++ compiler supporting at least C++14. Major compilers are
+- A compatible C++ compiler supporting at least C++11. Major compilers are
  supported. Refer to [Supported Compilers](./README.md#supported-c-versions)
  for more information.
 - [Git](https://git-scm.com/) for fetching opentelemetry-cpp source code from
  repository. To install Git, consult the [Set up
  Git](https://help.github.com/articles/set-up-git/) guide on GitHub.
 - [CMake](https://cmake.org/) for building opentelemetry-cpp API, SDK with their
-  unittests. The minimum CMake version is 3.14.
-  CMake 3.15+ is recommended on Windows due to known CI test failures with 3.14.
-  To install CMake,
+  unittests. We use CMake version 3.15.2 in our build system. To install CMake,
  consult the [Installing CMake](https://cmake.org/install/) guide.
 - [GoogleTest](https://github.com/google/googletest) framework to build and run
-  the unittests. Refer to
-  [third_party_release](https://github.com/open-telemetry/opentelemetry-cpp/blob/main/third_party_release#L5)
-  for version of GoogleTest used in CI. To install GoogleTest, consult the
-  [GoogleTest Build
+  the unittests. Refer to [third_party_release](https://github.com/open-telemetry/opentelemetry-cpp/blob/main/third_party_release#L5)
+  for version of GoogleTest used in CI. To
+  install GoogleTest, consult the [GoogleTest Build
  Instructions](https://github.com/google/googletest/blob/master/googletest/README.md#generic-build-instructions).
- [Google Benchmark](https://github.com/google/benchmark) framework to build and
-  run benchmark tests. Refer to
-  [third_party_release](https://github.com/open-telemetry/opentelemetry-cpp/blob/main/third_party_release#L4)
-  for version of Benchmark used in CI. To install Benchmark, consult the
-  [GoogleBenchmark Build
-  Instructions](https://github.com/google/benchmark#installation).
+- [Google Benchmark](https://github.com/google/benchmark) framework to build and run
+  benchmark tests. Refer to [third_party_release](https://github.com/open-telemetry/opentelemetry-cpp/blob/main/third_party_release#L4)
+  for version of Benchmark used in CI. To install Benchmark,
+  consult the [GoogleBenchmark Build Instructions](https://github.com/google/benchmark#installation).
 - Apart from above core requirements, the Exporters and Propagators have their
-  build dependencies.
-
-### Building dependencies for the OTLP exporters
-
-The opentelemetry-cpp OTLP exporters depend on Protobuf and gRPC
- (in the case of the otlp grpc exporters).
-Protobuf (since version 3.22.0) and gRPC depend on Abseil.
-For cmake builds, it is best practice to build and install Abseil
-, Protobuf, and gPRC as independent packages -
-configuring cmake for Protobuf and gRPC to build against
- the installed packages instead of using their submodule option.
-
-If building and installing Protobuf and gRPC manually with cmake the
- recommended approach is:
-
-1. Choose the desired tag version of grpc. Find the compatible versions of abseil
- and protobuf by inspecting the submodules of grpc at that tag.
-2. Build and install the required version of abseil
-3. Build and install the required version of protobuf
-    - Set the cmake option of Protobuf to build against the installed
-     package of Abseil (`protobuf_ABSL_PROVIDER=package`)
-4. Build and install the required version of grpc
-    - Set the cmake option of grpc to build against the installed packages
-     of Abseil and Protobuf (cmake options - `gRPC_ABSL_PROVIDER=package` and `gRPC_PROTOBUF_PROVIDER=package`)
+  build dependencies which are not covered here. E.g, Otlp Exporter needs
+  grpc/protobuf library, Zipkin exporter needs nlohmann-json and libcurl, ETW
+  exporter need nlohmann-json to build. This is covered in the build
+  instructions for each of these components.

 ### Building as standalone CMake Project

-1. Getting the opentelemetry-cpp source with its submodules:
+1. Getting the opentelementry-cpp source:

   ```console
   # Change to the directory where you want to create the code repository
   $ cd ~
-   $ mkdir source && cd source && git clone --recurse-submodules https://github.com/open-telemetry/opentelemetry-cpp
+   $ mkdir source && cd source
+   $ git clone --recursive https://github.com/open-telemetry/opentelemetry-cpp
   Cloning into 'opentelemetry-cpp'...
   ...
   Resolving deltas: 100% (3225/3225), done.
@ -84,7 +57,8 @@ If building and installing Protobuf and gRPC manually with cmake the

   ```console
   $ cd opentelemetry-cpp
-   $ mkdir build && cd build && cmake ..
+   $ mkdir build && cd build
+   $ cmake ..
   -- The C compiler identification is GNU 9.3.0
   -- The CXX compiler identification is GNU 9.3.0
   ...
@ -101,17 +75,14 @@ If building and installing Protobuf and gRPC manually with cmake the
     configuration, the code is compiled without `-fpic` option, so it is not
     suitable for inclusion in shared libraries. To enable the code for
     inclusion in shared libraries, this variable is used.
-   - `-DBUILD_SHARED_LIBS=ON` : To build shared libraries for the targets.
-      Please refer to note [below](#building-shared-libs-for-windows) for
-      Windows DLL support.
-   - `-DWITH_OTLP_GRPC=ON` : To enable building OTLP GRPC exporter.
-   - `-DWITH_OTLP_HTTP=ON` : To enable building OTLP HTTP exporter.
+   - `-DBUILD_SHARED_LIBS=ON` : To build shared libraries for the targets. Please
+      refer to note [below](#building-shared-libs-for-windows) for Windows DLL
+      support
+   - `-DWITH_OTLP=ON` : To enable building Otlp exporter.
   - `-DWITH_PROMETHEUS=ON` : To enable building prometheus exporter.
-   - `-DOPENTELEMETRY_INSTALL=ON`: To install `otel-cpp` library needed
-      for external code linking.

-3. Once the build configuration is created, build the CMake targets - this
-   includes building SDKs and unittests for API and SDK. Note that since API is
+3. Once build configuration is created, build the CMake targets - this includes
+   building SDKs, and building unittests for API and SDK. Note that since API is
   header only library, no separate build is triggered for it.

   ```console
@ -144,159 +115,57 @@ If building and installing Protobuf and gRPC manually with cmake the
   files for SDK at custom/default install location.

   ```console
-   $ cmake --install . --prefix /<install-root>/
+   $ cmake --install . --config Debug --prefix /<install_root>/
   -- Installing: /<install-root>/lib/cmake/opentelemetry-cpp/opentelemetry-cpp-config.cmake
   -- Installing: /<install-root>/lib/cmake/opentelemetry-cpp/opentelemetry-cpp-config-version.cmake
   ...
+   -- Installing: /<install-root>/include/opentelemetry//ext/zpages/static/tracez_index.h
+   -- Installing: /<install-root>/include/opentelemetry//ext/zpages/static/tracez_style.h
+   -- Installing: /<install-root>/include/opentelemetry//ext/zpages/threadsafe_span_data.h
+   -- Installing: /<install-root>/lib/libopentelemetry_zpages.a
   $
   ```

-### Incorporating into an external CMake Project
+### Incorporating into an existing CMake Project

-There are two approaches to incoporate `opentelemetry-cpp` into
- an external CMake project:
-
-1. Build and install `opentelemetry-cpp` then use `find_package`
- to import its targets
-
-   ```cmake
-   # Find all installed components and link all imported targets
-   find_package(opentelemetry-cpp CONFIG REQUIRED)
-   ...
-   target_include_directories(foo PRIVATE ${OPENTELEMETRY_CPP_INCLUDE_DIRS})
-   target_link_libraries(foo PRIVATE ${OPENTELEMETRY_CPP_LIBRARIES})
-   ```
-
-   ```cmake
-   # Find a specific component and link its imported target(s)
-   find_package(opentelemetry-cpp CONFIG REQUIRED COMPONENTS api)
-   ...
-   target_link_libraries(foo PRIVATE opentelemetry-cpp::api)
-   ```
-
-2. Use CMake's [FetchContent](https://cmake.org/cmake/help/latest/module/FetchContent.html)
- module to fetch and build `opentelemetry-cpp` then make its targets available
-
-   ```cmake
-   # Fetch from an existing clone and build
-   include(FetchContent)
-   FetchContent_Declare(opentelemetry-cpp SOURCE_DIR "<path/to/opentelemetry-cpp>")
-   FetchContent_MakeAvailable(opentelemetry-cpp)
-   ...
-   target_link_libraries(foo PRIVATE opentelemetry-cpp::api)
-   ```
-
-   ```cmake
-   # Clone and build opentelemetry-cpp from a git tag
-   include(FetchContent)
-   FetchContent_Declare(
-   opentelemetry-cpp
-   GIT_REPOSITORY https://github.com/open-telemetry/opentelemetry-cpp.git
-   GIT_TAG        v1.20.0)
-   FetchContent_MakeAvailable(opentelemetry-cpp)
-   ...
-   target_link_libraries(foo PRIVATE opentelemetry-cpp::api)
-   ```
-
-In both cases the project's built or imported CMake targets will be
- available in the `opentelemetry-cpp` namespace (ie: `opentelemetry-cpp::api`)
-
-#### Using opentelemetry-cpp package components
-
-> **Note:** `opentelemetry-cpp` CMake package components were introduced in `v1.21.0`
-
-The `opentelemetry-cpp` package supports using the `COMPONENTS` argument to
-`find_package`. The following example illustrates using this feature to include
-and link the `api` header only target to an instrumented `foo_lib` while only including
-and linking the `sdk` and `otlp_grpc_exporter` targets to the `foo_app`.
+To use the library from a CMake project, you can locate it directly with
+ `find_package` and use the imported targets from generated package
+ configurations. As of now, this will import targets for both API and SDK. In
+ future, there may be separate packages for API and SDK which can be installed
+ and imported separtely according to need.

 ```cmake
-# foo_lib/CMakeLists.txt
-find_package(opentelemetry-cpp CONFIG REQUIRED COMPONENTS api)
-add_library(foo_lib foo.cpp)
-target_link_libraries(foo_lib PRIVATE opentelemetry-cpp::api)
+# CMakeLists.txt
+find_package(opentelemetry-cpp CONFIG REQUIRED)
+...
+target_include_directories(foo PRIVATE ${OPENTELEMETRY_CPP_INCLUDE_DIRS})
+target_link_libraries(foo PRIVATE ${OPENTELEMETRY_CPP_LIBRARIES})
 ```

-```cmake
-# foo_app/CMakeLists.txt
-find_package(opentelemetry-cpp CONFIG REQUIRED COMPONENTS api sdk exporters_otlp_grpc)
-add_executable(foo_app main.cpp)
-target_link_libraries(foo_app PRIVATE foo_lib opentelemetry-cpp::api opentelemetry-cpp::trace opentelemetry-cpp::otlp_grpc_exporter )
-```
-
-The following table provides the mapping between components and targets. Components
-and targets available in the installation depends on the opentelemetry-cpp package
-build configuration.
-
-> **Note:** components `exporters_elasticsearch` and `exporters_etw`
- may be moved out of the core package and to `opentelemetry-cpp-contrib`
-  in a future release
-
-| Component                  | Targets                                                                                          |
-|----------------------------|--------------------------------------------------------------------------------------------------|
-| **api**                    | opentelemetry-cpp::api                                                                           |
-| **sdk**                    | opentelemetry-cpp::sdk                                                                           |
-|                            | opentelemetry-cpp::version                                                                       |
-|                            | opentelemetry-cpp::common                                                                        |
-|                            | opentelemetry-cpp::resources                                                                     |
-|                            | opentelemetry-cpp::trace                                                                         |
-|                            | opentelemetry-cpp::metrics                                                                       |
-|                            | opentelemetry-cpp::logs                                                                          |
-| **ext_common**             | opentelemetry-cpp::ext                                                                           |
-| **ext_http_curl**          | opentelemetry-cpp::http_client_curl                                                              |
-| **ext_dll**                | opentelemetry-cpp::opentelemetry_cpp                                                             |
-| **exporters_in_memory**    | opentelemetry-cpp::in_memory_span_exporter                                                       |
-|                            | opentelemetry-cpp::in_memory_metric_exporter                                                     |
-| **exporters_ostream**      | opentelemetry-cpp::ostream_log_record_exporter                                                   |
-|                            | opentelemetry-cpp::ostream_metrics_exporter                                                      |
-|                            | opentelemetry-cpp::ostream_span_exporter                                                         |
-| **exporters_otlp_common**  | opentelemetry-cpp::proto                                                                         |
-|                            | opentelemetry-cpp::otlp_recordable                                                               |
-| **exporters_otlp_file**    | opentelemetry-cpp::otlp_file_client                                                              |
-|                            | opentelemetry-cpp::otlp_file_exporter                                                            |
-|                            | opentelemetry-cpp::otlp_file_log_record_exporter                                                 |
-|                            | opentelemetry-cpp::otlp_file_metric_exporter                                                     |
-| **exporters_otlp_grpc**    | opentelemetry-cpp::proto_grpc                                                                    |
-|                            | opentelemetry-cpp::otlp_grpc_client                                                              |
-|                            | opentelemetry-cpp::otlp_grpc_exporter                                                            |
-|                            | opentelemetry-cpp::otlp_grpc_log_record_exporter                                                 |
-|                            | opentelemetry-cpp::otlp_grpc_metrics_exporter                                                    |
-| **exporters_otlp_http**    | opentelemetry-cpp::otlp_http_client                                                              |
-|                            | opentelemetry-cpp::otlp_http_exporter                                                            |
-|                            | opentelemetry-cpp::otlp_http_log_record_exporter                                                 |
-|                            | opentelemetry-cpp::otlp_http_metric_exporter                                                     |
-| **exporters_prometheus**   | opentelemetry-cpp::prometheus_exporter                                                           |
-| **exporters_elasticsearch**| opentelemetry-cpp::elasticsearch_log_record_exporter                                             |
-| **exporters_etw**          | opentelemetry-cpp::etw_exporter                                                                  |
-| **exporters_zipkin**       | opentelemetry-cpp::zipkin_trace_exporter                                                         |
-| **shims_opentracing**      | opentelemetry-cpp::opentracing_shim                                                              |
-
 ## Build instructions using Bazel

 NOTE: Experimental, and not supported for all the components. Make sure the
-[GoogleTest](https://github.com/google/googletest) installation may fail if
-there is a different version of googletest already installed in system-defined
-path.
+[GoogleTest](https://github.com/google/googletest) installation may fail if there is a different version of googletest already installed in system-defined path.

-### Prerequisites for Bazel build
+### Prerequisites for Bazel

- A supported platform (e.g. Windows, macOS or Linux). Refer to [Platforms
-Supported](./README.md#supported-development-platforms) for more information.
- A compatible C++ compiler supporting at least C++14. Major compilers are
-supported. Refer to [Supported Compilers](./README.md#supported-c-versions) for
-more information.
- [Git](https://git-scm.com/) for fetching opentelemetry-cpp source code from
-repository. To install Git, consult the [Set up
-Git](https://help.github.com/articles/set-up-git/) guide on GitHub.
- [Bazel](https://www.bazel.build/) for building opentelemetry-cpp API, SDK with
-their unittests. We use 3.7.2 in our build system.
+- A supported platform (e.g. Windows, macOS or Linux).
+Refer to [Platforms Supported](./README.md#supported-development-platforms)
+for more information.
+- A compatible C++ compiler supporting at least C++11.
+Major compilers are supported.
+Refer to [Supported Compilers](./README.md#supported-c-versions) for more information.
+- [Git](https://git-scm.com/) for fetching opentelemetry-cpp source code from repository.
+To install Git, consult the [Set up Git](https://help.github.com/articles/set-up-git/)
+guide on GitHub.
+- [Bazel](https://www.bazel.build/) for building opentelemetry-cpp API,
+SDK with their unittests. We use 3.7.2 in our build system.

-To install Bazel, consult the [Installing
-Bazel](https://docs.bazel.build/versions/3.7.0/install.html) guide.
+To install Bazel, consult the [Installing Bazel](https://docs.bazel.build/versions/3.7.0/install.html) guide.

 ### Building as standalone Bazel Project

-1. Getting the opentelemetry-cpp source:
+1. Getting the opentelementry-cpp source:

   ```console
   # Change to the directory where you want to create the code repository
@ -309,11 +178,10 @@ Bazel](https://docs.bazel.build/versions/3.7.0/install.html) guide.
   $
   ```

-2. Navigate to the repository cloned above, download the dependencies and build
-   the source code:
+2. Navigate to the repository cloned above, download the dependencies and build the source code:

   ```console
-   $ cd opentelemetry-cpp
+   $ cd opentelemtry-cpp
   $ bazel build //...
   bazel build -- //... -//exporters/otlp/... -//exporters/prometheus/...
   Extracting Bazel installation...
@ -354,11 +222,6 @@ load("@io_opentelemetry_cpp//bazel:repository.bzl", "opentelemetry_cpp_deps")

 opentelemetry_cpp_deps()

-# (required after v1.8.0) Load extra dependencies required for OpenTelemetry
-load("@io_opentelemetry_cpp//bazel:extra_deps.bzl", "opentelemetry_extra_deps")
-
-opentelemetry_extra_deps()
-
 # Load gRPC dependencies after load.
 load("@com_github_grpc_grpc//bazel:grpc_deps.bzl", "grpc_deps")

@ -389,64 +252,23 @@ cc_library(

 ## Building shared libs for Windows

-Windows DLL build is supported under **preview**. Please check the
-[doc](./docs/build-as-dll.md) for more details.
-
-## Generating binary packages
-
-OpenTelemetry C++ supports generating platform specific binary packages from CMake
-configuration. The packages generated through this mayn't be production ready,
-and user may have to customize it further before using it as distribution.
-
- Linux : deb, rpm, tgz
- MacOS : tgz
- Windows : NuGet, zip
-
-This requires platform specific package generators already installed. The package
-generation can subsequently be enabled by using BUILD_PACKAGE option during cmake
-configuration
-
-   ```console
-   $ cd opentelemetry-cpp
-   $ mkdir build && cd build && cmake -DBUILD_PACKAGE=ON ..
-
-   -- Package name: opentelemetry-cpp-1.8.1-ubuntu-20.04-x86_64.deb
-   -- Configuring done
-   -- Generating done
-   ...
-   $
-   ```
-
-Once build is complete as specified in [standalone build section](#building-as-standalone-cmake-project),
-the package can be generated as below.
-
-   ```console
-   $ cpack -C debug
-   CPack: Create package using DEB
-   ...
-   CPack: - package: /home/<user>/opentelemetry-cpp/build/opentelemetry-cpp-1.8.1-ubuntu-20.04-x86_64.deb generated.
-   $
-   ```
+Windows DLL build is not supported. There are some constraints on how C++ DLLs work on
+Windows, specifically we can't safely allocate memory in one DLL and free it in another.
+For now, OpenTelemetry C++ targets need to be statically linked into the Windows applications.

 ## Using Package Managers

-If you are using [Conan](https://www.conan.io/) to manage your dependencies, add
-[`opentelemetry-cpp/x.y.z`](https://conan.io/center/opentelemetry-cpp) to your
-`conanfile`'s requires, where `x.y.z` is the release version you want to use.
+If you are using [Conan](https://www.conan.io/) to manage your dependencies,
+add [`opentelemetry-cpp/x.y.z`](https://conan.io/center/opentelemetry-cpp) to
+your `conanfile`'s requires, where `x.y.z` is the release version you want to use.
 Please file issues [here](https://github.com/conan-io/conan-center-index/issues)
 if you experience problems with the packages.

 If you are using [vcpkg](https://github.com/Microsoft/vcpkg/) on your project
-for external dependencies, then you can install the [opentelemetry-cpp
-package](https://github.com/microsoft/vcpkg/tree/master/ports/opentelemetry-cpp)
-with `vcpkg install opentelemetry-cpp` and follow the then displayed
-descriptions. Please see the vcpkg project for any issues regarding the
-packaging.
+for external dependencies, then you can install the
+[opentelemetry-cpp package](https://github.com/microsoft/vcpkg/tree/master/ports/opentelemetry-cpp)
+with `vcpkg install opentelemetry-cpp` and follow the then displayed descriptions.
+Please see the vcpkg project for any issues regarding the packaging.

-If you are using [alpine linux](https://www.alpinelinux.org/) you can install
-the [opentelemetry-cpp packages](https://pkgs.alpinelinux.org/packages?name=opentelemetry-cpp-*)
-with `apk add -X http://dl-cdn.alpinelinux.org/alpine/edge/testing opentelemetry-cpp-dev`.
-
-Please note, these packages are not officially provided and maintained by
-OpenTelemetry C++ project, and are just listed here to consolidate all such
-efforts for ease of developers.
+Please note, these packages are not officially provided and maintained by OpenTelemetry C++ project,
+and are just listed here to consolidate all such efforts for ease of developers.
--- a/MODULE.bazel
+++ b/MODULE.bazel
@ -1,25 +0,0 @@
-# Copyright The OpenTelemetry Authors
-# SPDX-License-Identifier: Apache-2.0
-
-module(
-    name = "opentelemetry-cpp",
-    version = "1.22.0",
-    compatibility_level = 0,
-    repo_name = "io_opentelemetry_cpp",
-)
-
-bazel_dep(name = "abseil-cpp", version = "20240116.1", repo_name = "com_google_absl")
-bazel_dep(name = "bazel_skylib", version = "1.5.0")
-bazel_dep(name = "curl", version = "8.8.0")
-bazel_dep(name = "grpc", version = "1.63.1.bcr.1", repo_name = "com_github_grpc_grpc")
-bazel_dep(name = "nlohmann_json", version = "3.12.0", repo_name = "github_nlohmann_json")
-bazel_dep(name = "opentelemetry-proto", version = "1.7.0", repo_name = "com_github_opentelemetry_proto")
-bazel_dep(name = "opentracing-cpp", version = "1.6.0", repo_name = "com_github_opentracing")
-bazel_dep(name = "platforms", version = "0.0.8")
-bazel_dep(name = "prometheus-cpp", version = "1.3.0", repo_name = "com_github_jupp0r_prometheus_cpp")
-bazel_dep(name = "protobuf", version = "26.0", repo_name = "com_google_protobuf")
-bazel_dep(name = "rules_proto", version = "5.3.0-21.7")
-bazel_dep(name = "zlib", version = "1.3.1.bcr.1")
-
-bazel_dep(name = "google_benchmark", version = "1.8.3", dev_dependency = True, repo_name = "com_github_google_benchmark")
-bazel_dep(name = "googletest", version = "1.14.0.bcr.1", dev_dependency = True, repo_name = "com_google_googletest")
--- a/README.md
+++ b/README.md
@ -5,27 +5,37 @@
 [![Build
 Status](https://github.com/open-telemetry/opentelemetry-cpp/actions/workflows/ci.yml/badge.svg?branch=main)](https://github.com/open-telemetry/opentelemetry-cpp/actions)
 [![Release](https://img.shields.io/github/v/release/open-telemetry/opentelemetry-cpp?include_prereleases&style=)](https://github.com/open-telemetry/opentelemetry-cpp/releases/)
-[![FOSSA License Status](https://app.fossa.com/api/projects/custom%2B162%2Fgithub.com%2Fopen-telemetry%2Fopentelemetry-cpp.svg?type=shield&issueType=license)](https://app.fossa.com/projects/custom%2B162%2Fgithub.com%2Fopen-telemetry%2Fopentelemetry-cpp?ref=badge_shield&issueType=license)
-[![FOSSA Security Status](https://app.fossa.com/api/projects/custom%2B162%2Fgithub.com%2Fopen-telemetry%2Fopentelemetry-cpp.svg?type=shield&issueType=security)](https://app.fossa.com/projects/custom%2B162%2Fgithub.com%2Fopen-telemetry%2Fopentelemetry-cpp?ref=badge_shield&issueType=security)

 The C++ [OpenTelemetry](https://opentelemetry.io/) client.

 ## Project Status

-**Stable** across all 3 signals i.e. `Logs`, `Metrics`, and `Traces`.
+| Signal  | Status                 | Project                                                                  |
+| ------- | ---------------------- | ------------------------------------------------------------------------ |
+| Traces  | Public Release         | N/A                                                                      |
+| Metrics | Development  [1]       | N/A                                                                      |
+| Logs    | Experimental [2]       | N/A                                                                      |

-See [Spec Compliance
-Matrix](https://github.com/open-telemetry/opentelemetry-specification/blob/main/spec-compliance-matrix.md)
-to understand which portions of the specification has been implemented in this
-repo.
+* [1]: The development of the metrics API and SDK based on new stable specification is ongoing. The timelines would be available in release milestone. The earlier implementation (based on old specification) can be included in build by setting `ENABLE_METRICS_PREVIEW` preprocessor macro, and is included under `*/_metrics/*` directory. This would be eventually removed once the ongoing implemetation is stable.
+* [2]: The current Log Signal Implementation is Experimental, and will change as the current OpenTelemetry Log specification matures. The current implementation can be included in build by setting `ENABLE_LOGS_PREVIEW` preprocessor macro.
+
+## OpenTelemetry Specification Compatibility Matrix
+
+| API Version | Core Version | Contrib Version         |
+| ----------- |--------------|-------------------------|
+| 1.0.0       | 1.0.0-rc4    | N/A [1]                 |
+| 1.0.0       | 1.0.0        | N/A                     |
+
+* [1]: We don't have releases for opentelemetry-cpp contrib repo. This may change in future.

 ## Supported C++ Versions

 Code shipped from this repository generally supports the following versions of
 C++ standards:

-* ISO/IEC 14882:2014 (C++14)
-* ISO/IEC 14882:2017 (C++17)
+* ISO/IEC 14882:2011 (C++11, C++0x)
+* ISO/IEC 14882:2014 (C++14, C++1y)
+* ISO/IEC 14882:2017 (C++17, C++1z)
 * ISO/IEC 14882:2020 (C++20)

 Any exceptions to this are noted in the individual `README.md` files.
@ -40,20 +50,23 @@ of the current project.

 | Platform                                                            |   Build type  |
 |---------------------------------------------------------------------|---------------|
-| ubuntu-22.04 (GCC 10, GCC 12, Clang 14)                             | CMake, Bazel  |
-| ubuntu-20.04 (GCC 9.4.0 - default compiler)                         | CMake, Bazel  |
-| ubuntu-20.04 (GCC 9.4.0 with -std=c++14/17/20 flags)                | CMake, Bazel  |
-| macOS 12.7 (Xcode 14.2)                                             | Bazel         |
+| ubuntu-20.04 (Default GCC Compiler - 9.3.0)                         | CMake, Bazel  |
+| ubuntu-18.04 (GCC 4.8 with -std=c++11 flag)                         | CMake [1]     |
+| ubuntu-20.04 (Default GCC Compiler - 9.3.0 with -std=c++20 flags)   | CMake, Bazel  |
+| macOS 10.15 (Xcode 12.2)                                            | Bazel         |
 | Windows Server 2019 (Visual Studio Enterprise 2019)                 | CMake, Bazel  |
-| Windows Server 2022 (Visual Studio Enterprise 2022)                 | CMake         |
+
+[1]: Bazel build is disabled for GCC 4.8, as gRPC library 1.38 and above
+  (required by OTLP expoter) don't build with this compiler. See gRPC [official
+  support](https://grpc.io/docs/#official-support) document. CMake build doesn't
+  build OTLP exporter with GCC 4.8.

 In general, the code shipped from this repository should build on all platforms
 having C++ compiler with [supported C++ standards](#supported-c-versions).

 ## Dependencies

-Please refer to [Dependencies.md](docs/dependencies.md) for OSS Dependencies and
-license requirements.
+Please refer to [Dependencies.md](docs/dependencies.md) for OSS Dependencies and license requirements.

 ## Installation

@ -61,9 +74,7 @@ Please refer to [INSTALL.md](./INSTALL.md).

 ## Getting Started

-As an application owner or the library author, you can find the getting started
-guide and reference documentation on
-[opentelemetry-cpp.readthedocs.io](https://opentelemetry-cpp.readthedocs.io/en/latest/)
+As an application owner or the library author, you can find the getting started guide and reference documentation on [opentelemetry-cpp.readthedocs.io](https://opentelemetry-cpp.readthedocs.io/en/latest/)

 The `examples/simple` directory contains a minimal program demonstrating how to
 instrument a small library using a simple `processor` and console `exporter`,
@ -73,10 +84,10 @@ along with build files for CMake and Bazel.

 See [CONTRIBUTING.md](CONTRIBUTING.md)

-We meet weekly, and the time of the meeting alternates between Monday at 13:00
-PT and Wednesday at 9:00 PT. The meeting is subject to change depending on
+We meet weekly, and the time of the meeting alternates between Monday at 15:00
+PT and Wednesday at 10:00 PT. The meeting is subject to change depending on
 contributors' availability. Check the [OpenTelemetry community
-calendar](https://github.com/open-telemetry/community#calendar)
+calendar](https://calendar.google.com/calendar/embed?src=google.com_b79e3e90j7bbsa2n2p5an5lf60%40group.calendar.google.com)
 for specific dates and Zoom meeting links.

 Meeting notes are available as a public [Google
@ -84,35 +95,36 @@ doc](https://docs.google.com/document/d/1i1E4-_y4uJ083lCutKGDhkpi3n4_e774SBLi9hP
 For edit access, get in touch on
 [Slack](https://cloud-native.slack.com/archives/C01N3AT62SJ).

-### Maintainers
+Approvers
+([@open-telemetry/cpp-approvers](https://github.com/orgs/open-telemetry/teams/cpp-approvers)):

-* [Ehsan Saei](https://github.com/esigo)
+* [Johannes Tax](https://github.com/pyohannes), Microsoft
+* [Josh Suereth](https://github.com/jsuereth), Google
+* [Max Golovanov](https://github.com/maxgolov), Microsoft
+* [Ryan Burn](https://github.com/rnburn), Lightstep
+
+*Find more about the approver role in [community
+repository](https://github.com/open-telemetry/community/blob/main/community-membership.md#approver).*
+
+Maintainers
+([@open-telemetry/cpp-maintainers](https://github.com/orgs/open-telemetry/teams/cpp-maintainers)):
+
+* [Emil Mikulic](https://github.com/g-easy), Google
 * [Lalit Kumar Bhasin](https://github.com/lalitb), Microsoft
-* [Marc Alff](https://github.com/marcalff), Oracle
+* [Reiley Yang](https://github.com/reyang), Microsoft
 * [Tom Tan](https://github.com/ThomsonTan), Microsoft

-For more information about the maintainer role, see the [community repository](https://github.com/open-telemetry/community/blob/main/guides/contributor/membership.md#maintainer).
+*Find more about the maintainer role in [community
+repository](https://github.com/open-telemetry/community/blob/main/community-membership.md#maintainer).*

-### Approvers
+Triagers
+([@open-telemetry/cpp-triagers](https://github.com/orgs/open-telemetry/teams/cpp-triagers)):

-* [Doug Barker](https://github.com/dbarker)
-* [Josh Suereth](https://github.com/jsuereth), Google
-* [Pranav Sharma](https://github.com/psx95), Google
-* [WenTao Ou](https://github.com/owent), Tencent
+* [Alolita Sharma](https://github.com/alolita), Amazon
+* [Jodee Varney](https://github.com/jodeev), New Relic

-For more information about the approver role, see the [community repository](https://github.com/open-telemetry/community/blob/main/guides/contributor/membership.md#approver).
-
-### Emeritus Maintainer/Approver/Triager
-
-* [Alolita Sharma](https://github.com/alolita)
-* [Emil Mikulic](https://github.com/g-easy)
-* [Jodee Varney](https://github.com/jodeev)
-* [Johannes Tax](https://github.com/pyohannes)
-* [Max Golovanov](https://github.com/maxgolov)
-* [Reiley Yang](https://github.com/reyang)
-* [Ryan Burn](https://github.com/rnburn)
-
-For more information about the emeritus role, see the [community repository](https://github.com/open-telemetry/community/blob/main/guides/contributor/membership.md#emeritus-maintainerapprovertriager).
+*Find more about the triager role in [community
+repository](https://github.com/open-telemetry/community/blob/main/community-membership.md#triager).*

 ### Thanks to all the people who have contributed

@ -120,6 +132,8 @@ For more information about the emeritus role, see the [community repository](htt

 ## Release Schedule

+Refer to [project status](#project-status) for current status of the project.
+
 See the [release
 notes](https://github.com/open-telemetry/opentelemetry-cpp/releases) for
 existing releases.
--- a/RELEASING.md
+++ b/RELEASING.md
@ -2,27 +2,24 @@

 ## Pre Release

-1: Upgrade to latest [dependencies](docs/maintaining-dependencies.md)
-if required.
-
-2: Make sure all relevant changes for this release are included under
+1: Make sure all relevant changes for this release are included under
 `Unreleased` section in `CHANGELOG.md` and are in language that non-contributors
 to the project can understand.

-3: Run the pre-release script. It creates a branch `pre_release_<new-tag>` and
+2: Run the pre-release script. It creates a branch `pre_release_<new-tag>` and
 updates `CHANGELOG.md` with the `<new-tag>`:

 ```sh
 ./buildscripts/pre_release.sh -t <new-tag>
 ```

-4: Verify that CHANGELOG.md is updated properly:
+3: Verify that CHANGELOG.md is updated properly:

 ```sh
 git diff main
 ```

-5: Push the changes to upstream and create a Pull Request on GitHub. Be sure to
+4: Push the changes to upstream and create a Pull Request on GitHub. Be sure to
 include the curated changes from the [Changelog](./CHANGELOG.md) in the
 description.

@ -92,5 +89,5 @@ should include all the release notes from the Changelog for this release.
 ## Post Release

 Update the OpenTelemetry.io document
-[here](https://github.com/open-telemetry/opentelemetry.io/tree/main/content/en/docs/instrumentation/cpp)
+[here](https://github.com/open-telemetry/opentelemetry.io/tree/main/content/en/docs/cpp)
 by sending a Pull Request.
--- a/Versioning.md
+++ b/Versioning.md
@ -19,20 +19,20 @@ buy may not work in applications using `opentelemetry 2.0.0`.

 Refer to the [ABI Policy](./docs/abi-policy.md) for more details. To summarise:

-* The API is header only, and uses ABI compliant interfaces. However, ABI
-  stability is not guaranteed for SDK.
-* In case of ABI breaking changes, a new `inline namespace` version will be
-  introduced, and the existing linked applications can continue using the older
-  version unless they relink with newer version.
+* The API is header only, and uses ABI compliant interfaces. However, ABI stability
+  is not guaranteed for SDK.
+* In case of ABI breaking changes, a new `inline namespace` version will
+  be introduced, and the existing linked applications can continue using the older version
+  unless they relink with newer version.

 ## Release Policy

 * Release versions will follow [SemVer 2.0](https://semver.org/).
 * Only a single source package containing the API, SDK, and exporters which are
  required by the specification would be released. All these components are
-  always versioned and released together. For example, any changes in one of the
-  exporter would result in version update of the entire source package even
-  though there is no changes in API, SDK and other exporters.
+  always versioned and released together. For example, any changes in one of the exporter
+  would result in version update of the entire source package even though there is
+  no changes in API, SDK and other exporters.
 * Experimental releases: New (unstable) telemetry signals and features will be
  introduced behind feature flag protected by a preprocessor macro.

@ -52,7 +52,7 @@ Refer to the [ABI Policy](./docs/abi-policy.md) for more details. To summarise:

  * Naming:
    * `ENABLE_<SIGNAL>_PREVIEW` : For experimental release of signal api/sdks
-      eg, `METRICS_PREVIEW`, `LOGS_PREVIEW`,
+      eg, `METRICS_PREVIEW`, `LOGGING_PREVIEW`,
    * `ENABLE_<SIGNAL>_<FEATURE_NAME>_PREVIEW` : For experimental release for
      any feature within stable signal. For example, `TRACING_JAEGER_PREVIEW` to
      release the experimental Jaeger exporter for tracing.
@ -65,19 +65,16 @@ Refer to the [ABI Policy](./docs/abi-policy.md) for more details. To summarise:
  allowed to break existing stable interfaces. Feature flags will be removed
  once we have a stable implementation for the signal.

-* As an exception, small experimental features in otherwise stable
-  signals/components mayn't necessarily be released under feature flag. These
-  would be flagged as experimental by adding a `NOTE` in it's header file -
-  either at the beginning of file, or as the comment for the experimental API
-  methods. Also, if the complete header is experimental, it would be prefixed as
-  `experimental_`. As an example, the semantic conventions for trace signal is
-  experimental at the time of the writing and is within
-  `experimental_semantic_conventions.h`
+* As an exception, small experimental features in otherwise stable signals/components
+  mayn't necessarily be released under feature flag. These would be flagged as experimental
+  by adding a `NOTE` in it's header file - either at the beginning of file, or as the comment for
+  the experimental API methods. Also, if the complete header is experimental, it would be prefixed
+  as `experimental_`. As an example, the semantic conventions for
+  trace signal is experimental at the time of the writing and is within `experimental_semantic_conventions.h`

-* Code under the "*::detail" namespace implements internal details, and is NOT
-  part of public interface. Also, any API not documented in the [public
-  documentation](https://opentelemetry-cpp.readthedocs.io/en/latest/) is NOT
-  part of the public interface.
+* Code under the "*::detail" namespace implements internal details,
+  and NOT part of public interface. Also, any API not documented in the [public
+  documentation](https://opentelemetry-cpp.readthedocs.io/en/latest/) is NOT part of public interface.

 * GitHub releases will be made for all released versions.

--- a/59
+++ b/59
@ -1,5 +1,16 @@
-# Copyright The OpenTelemetry Authors
-# SPDX-License-Identifier: Apache-2.0
+# Copyright 2019, OpenTelemetry Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.

 workspace(name = "io_opentelemetry_cpp")

@ -8,10 +19,6 @@ load("//bazel:repository.bzl", "opentelemetry_cpp_deps")

 opentelemetry_cpp_deps()

-load("//bazel:extra_deps.bzl", "opentelemetry_extra_deps")
-
-opentelemetry_extra_deps()
-
 # Load gRPC dependencies after load.
 load("@com_github_grpc_grpc//bazel:grpc_deps.bzl", "grpc_deps")

@ -21,3 +28,43 @@ grpc_deps()
 load("@com_github_grpc_grpc//bazel:grpc_extra_deps.bzl", "grpc_extra_deps")

 grpc_extra_deps()
+
+load("@com_github_grpc_grpc//bazel:cc_grpc_library.bzl", "cc_grpc_library")
+load("@upb//bazel:workspace_deps.bzl", "upb_deps")
+
+upb_deps()
+
+# Load prometheus C++ dependencies.
+load("@com_github_jupp0r_prometheus_cpp//bazel:repositories.bzl", "prometheus_cpp_repositories")
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+
+http_archive(
+    name = "rules_foreign_cc",
+    sha256 = "69023642d5781c68911beda769f91fcbc8ca48711db935a75da7f6536b65047f",
+    strip_prefix = "rules_foreign_cc-0.6.0",
+    url = "https://github.com/bazelbuild/rules_foreign_cc/archive/0.6.0.tar.gz",
+)
+
+load("@rules_foreign_cc//foreign_cc:repositories.bzl", "rules_foreign_cc_dependencies")
+
+rules_foreign_cc_dependencies()
+
+_ALL_CONTENT = """\
+filegroup(
+    name = "all_srcs",
+    srcs = glob(["**"]),
+    visibility = ["//visibility:public"],
+)
+"""
+
+http_archive(
+    name = "thrift",
+    build_file_content = _ALL_CONTENT,
+    sha256 = "5ae1c4d16452a22eaf9d802ba7489907147c2b316ff38c9758918552fae5132c",
+    strip_prefix = "thrift-0.14.1",
+    urls = [
+        "https://github.com/apache/thrift/archive/refs/tags/v0.14.1.tar.gz",
+    ],
+)
+
+prometheus_cpp_repositories()
--- a/WORKSPACE.bzlmod
+++ b/WORKSPACE.bzlmod
@ -1,4 +0,0 @@
-# Copyright The OpenTelemetry Authors
-# SPDX-License-Identifier: Apache-2.0
-
-# Disables the default WORKSPACE when using bzlmod
--- a/api/BUILD
+++ b/api/BUILD
@ -1,81 +1,22 @@
-# Copyright The OpenTelemetry Authors
-# SPDX-License-Identifier: Apache-2.0
-
-load("@bazel_skylib//rules:common_settings.bzl", "bool_flag", "int_flag", "string_flag")
+# Copyright 2019, OpenTelemetry Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.

 package(default_visibility = ["//visibility:public"])

-CPP_STDLIBS = [
-    "none",
-    "best",
-    "2014",
-    "2017",
-    "2020",
-    "2023",
-]
-
-string_flag(
-    name = "with_cxx_stdlib",
-    build_setting_default = "best",
-    values = CPP_STDLIBS,
-)
-
 cc_library(
    name = "api",
    hdrs = glob(["include/**/*.h"]),
-    defines = select({
-        ":set_cxx_stdlib_none": [],
-        ### automatic selection
-        ":set_cxx_stdlib_best": ["OPENTELEMETRY_STL_VERSION=(__cplusplus/100)"],
-        # See https://learn.microsoft.com/en-us/cpp/build/reference/zc-cplusplus
-        ":set_cxx_stdlib_best_and_msvc": ["OPENTELEMETRY_STL_VERSION=(_MSVC_LANG/100)"],
-        ### manual selection
-        ":set_cxx_stdlib_2014": ["OPENTELEMETRY_STL_VERSION=2014"],
-        ":set_cxx_stdlib_2017": ["OPENTELEMETRY_STL_VERSION=2017"],
-        ":set_cxx_stdlib_2020": ["OPENTELEMETRY_STL_VERSION=2020"],
-        ":set_cxx_stdlib_2023": ["OPENTELEMETRY_STL_VERSION=2023"],
-        "//conditions:default": [],
-    }) + select({
-        ":abi_version_no_1": ["OPENTELEMETRY_ABI_VERSION_NO=1"],
-        ":abi_version_no_2": ["OPENTELEMETRY_ABI_VERSION_NO=2"],
-    }),
    strip_include_prefix = "include",
    tags = ["api"],
-    deps = [
-        "@com_google_absl//absl/base",
-        "@com_google_absl//absl/strings",
-        "@com_google_absl//absl/types:variant",
-    ],
-)
-
-[config_setting(
-    name = "set_cxx_stdlib_%s" % v,
-    flag_values = {":with_cxx_stdlib": v},
-) for v in CPP_STDLIBS]
-
-config_setting(
-    name = "set_cxx_stdlib_best_and_msvc",
-    constraint_values = ["@bazel_tools//tools/cpp:msvc"],
-    flag_values = {":with_cxx_stdlib": "best"},
-)
-
-bool_flag(
-    name = "with_abseil",
-    build_setting_default = False,
-    deprecation = "The value of this flag is ignored. Bazel builds always depend on Abseil for its pre-adopted `std::` types. You should remove this flag from your build command.",
-)
-
-int_flag(
-    name = "abi_version_no",
-    build_setting_default = 1,
-)
-
-config_setting(
-    name = "abi_version_no_1",
-    flag_values = {":abi_version_no": "1"},
-)
-
-config_setting(
-    name = "abi_version_no_2",
-    flag_values = {":abi_version_no": "2"},
 )
--- a/api/CHANGELOG.md
+++ b/api/CHANGELOG.md
@ -0,0 +1,26 @@
+# Release History: opentelemetry-api
+
+All notable changes to the api project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## Guideline to update the version
+
+Increment the:
+
+* MAJOR version when you make incompatible API/ABI changes,
+* MINOR version when you add functionality in a backwards compatible manner, and
+* PATCH version when you make backwards compatible bug fixes.
+
+## [Unreleased]
+
+## [0.1.0] 2020-12-17
+
+### Added
+
+* Trace API experimental
+
+### Changed
+
+### Removed
--- a/api/CMakeLists.txt
+++ b/api/CMakeLists.txt
@ -1,6 +1,3 @@
-# Copyright The OpenTelemetry Authors
-# SPDX-License-Identifier: Apache-2.0
-
 add_library(opentelemetry_api INTERFACE)
 target_include_directories(
  opentelemetry_api
@ -9,130 +6,61 @@ target_include_directories(

 set_target_properties(opentelemetry_api PROPERTIES EXPORT_NAME api)

-unset(TARGET_DEPS)
+install(
+  TARGETS opentelemetry_api
+  EXPORT "${PROJECT_NAME}-target"
+  RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
+  LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
+  ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR})
+
+set(LOGS_EXCLUDE_PATTERN "")
+if(NOT WITH_LOGS_PREVIEW)
+  set(LOGS_EXCLUDE_PATTERN "logs")
+endif()
+
+set(METRICS_EXCLUDE_PATTERN "")
+if(NOT WITH_METRICS_PREVIEW)
+  set(METRICS_EXCLUDE_PATTERN "metrics")
+endif()
+
+install(
+  DIRECTORY include/opentelemetry
+  DESTINATION include
+  FILES_MATCHING
+  PATTERN "*.h"
+  PATTERN "${METRICS_EXCLUDE_PATTERN}" EXCLUDE)
+
+install(
+  DIRECTORY include/opentelemetry
+  DESTINATION include
+  FILES_MATCHING
+  PATTERN "*.h"
+  PATTERN "${LOGS_EXCLUDE_PATTERN}" EXCLUDE)

 if(BUILD_TESTING)
  add_subdirectory(test)
 endif()

-if(WITH_NO_DEPRECATED_CODE)
-  target_compile_definitions(opentelemetry_api
-                             INTERFACE OPENTELEMETRY_NO_DEPRECATED_CODE)
+if(WITH_ABSEIL)
+  target_compile_definitions(opentelemetry_api INTERFACE HAVE_ABSEIL)
 endif()

-if(WITH_STL STREQUAL "OFF")
-  message(STATUS "Building WITH_STL=OFF")
-elseif(WITH_STL STREQUAL "CXX11")
-  message(STATUS "Building WITH_STL=CXX11")
-  target_compile_definitions(opentelemetry_api
-                             INTERFACE OPENTELEMETRY_STL_VERSION=2011)
-elseif(WITH_STL STREQUAL "CXX14")
-  message(STATUS "Building WITH_STL=CXX14")
-  target_compile_definitions(opentelemetry_api
-                             INTERFACE OPENTELEMETRY_STL_VERSION=2014)
-elseif(WITH_STL STREQUAL "CXX17")
-  message(STATUS "Building WITH_STL=CXX17")
-  target_compile_definitions(opentelemetry_api
-                             INTERFACE OPENTELEMETRY_STL_VERSION=2017)
-elseif(WITH_STL STREQUAL "CXX20")
-  message(STATUS "Building WITH_STL=CXX20")
-  target_compile_definitions(opentelemetry_api
-                             INTERFACE OPENTELEMETRY_STL_VERSION=2020)
-elseif(WITH_STL STREQUAL "CXX23")
-  message(STATUS "Building WITH_STL=CXX23")
-  target_compile_definitions(opentelemetry_api
-                             INTERFACE OPENTELEMETRY_STL_VERSION=2023)
-elseif(WITH_STL STREQUAL "CXX26")
-  message(STATUS "Building WITH_STL=CXX26")
-  target_compile_definitions(opentelemetry_api
-                             INTERFACE OPENTELEMETRY_STL_VERSION=2026)
-elseif(WITH_STL STREQUAL "ON")
-  message(STATUS "Building WITH_STL=ON")
-  # "ON" corresponds to "CXX23" at this time.
-  target_compile_definitions(opentelemetry_api
-                             INTERFACE OPENTELEMETRY_STL_VERSION=2023)
+if(WITH_STL)
+  message("Building with standard library types...")
+  target_compile_definitions(opentelemetry_api INTERFACE HAVE_CPP_STDLIB
+                                                         HAVE_GSL)
 else()
-  message(
-    FATAL_ERROR
-      "WITH_STL must be ON, OFF, CXX11, CXX14, CXX17, CXX20, CXX23 or CXX26")
+  message("Building with nostd types...")
 endif()

-if(WITH_GSL)
-  target_compile_definitions(opentelemetry_api INTERFACE HAVE_GSL)
-  target_link_libraries(opentelemetry_api INTERFACE Microsoft.GSL::GSL)
-  list(APPEND TARGET_DEPS "gsl")
+if(WITH_METRICS_PREVIEW)
+  target_compile_definitions(opentelemetry_api INTERFACE ENABLE_METRICS_PREVIEW)
 endif()

-if(WITH_NO_GETENV)
-  target_compile_definitions(opentelemetry_api INTERFACE NO_GETENV)
+if(WITH_LOGS_PREVIEW)
+  target_compile_definitions(opentelemetry_api INTERFACE ENABLE_LOGS_PREVIEW)
 endif()

-if(WIN32)
-  if(WITH_ETW)
-    target_compile_definitions(opentelemetry_api INTERFACE HAVE_MSGPACK)
-  endif()
-endif()
-
-if(WITH_ASYNC_EXPORT_PREVIEW)
-  target_compile_definitions(opentelemetry_api INTERFACE ENABLE_ASYNC_EXPORT)
-endif()
-
-target_compile_definitions(
-  opentelemetry_api
-  INTERFACE OPENTELEMETRY_ABI_VERSION_NO=${OPENTELEMETRY_ABI_VERSION_NO})
-
-if(WITH_OTLP_RETRY_PREVIEW)
-  target_compile_definitions(opentelemetry_api
-                             INTERFACE ENABLE_OTLP_RETRY_PREVIEW)
-endif()
-
-if(WITH_OTLP_GRPC_SSL_MTLS_PREVIEW)
-  target_compile_definitions(opentelemetry_api
-                             INTERFACE ENABLE_OTLP_GRPC_SSL_MTLS_PREVIEW)
-endif()
-
-if(WITH_OTLP_GRPC_CREDENTIAL_PREVIEW)
-  target_compile_definitions(opentelemetry_api
-                             INTERFACE ENABLE_OTLP_GRPC_CREDENTIAL_PREVIEW)
-endif()
-
-if(WITH_METRICS_EXEMPLAR_PREVIEW)
-  target_compile_definitions(opentelemetry_api
-                             INTERFACE ENABLE_METRICS_EXEMPLAR_PREVIEW)
-endif()
-
-if(WITH_THREAD_INSTRUMENTATION_PREVIEW)
-  target_compile_definitions(opentelemetry_api
-                             INTERFACE ENABLE_THREAD_INSTRUMENTATION_PREVIEW)
-endif()
-
-if(WITH_OTLP_HTTP_COMPRESSION)
-  target_compile_definitions(opentelemetry_api
-                             INTERFACE ENABLE_OTLP_COMPRESSION_PREVIEW)
-endif()
-
-if(APPLE)
-  target_link_libraries(opentelemetry_api INTERFACE "-framework CoreFoundation")
-endif()
-
-otel_add_component(
-  COMPONENT
-  api
-  TARGETS
-  opentelemetry_api
-  FILES_DIRECTORY
-  "include/opentelemetry"
-  FILES_DESTINATION
-  "include"
-  FILES_MATCHING
-  PATTERN
-  "*.h")
-
-include(${PROJECT_SOURCE_DIR}/cmake/pkgconfig.cmake)
-
-if(OPENTELEMETRY_INSTALL)
-  opentelemetry_add_pkgconfig(
-    api "OpenTelemetry API"
-    "A header-only library to support instrumentation with OpenTelemetry."
-    "${TARGET_DEPS}")
+if(CORE_RUNTIME_LIBS)
+  target_link_libraries(opentelemetry_api INTERFACE ${CORE_RUNTIME_LIBS})
 endif()
--- a/api/include/opentelemetry/_metrics/async_instruments.h
+++ b/api/include/opentelemetry/_metrics/async_instruments.h
@ -0,0 +1,88 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+#ifdef ENABLE_METRICS_PREVIEW
+
+#  include "opentelemetry/_metrics/instrument.h"
+#  include "opentelemetry/_metrics/observer_result.h"
+
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace metrics
+{
+
+template <class T>
+class ValueObserver : virtual public AsynchronousInstrument<T>
+{
+
+public:
+  ValueObserver() = default;
+
+  ValueObserver(nostd::string_view name,
+                nostd::string_view description,
+                nostd::string_view unit,
+                bool enabled,
+                void (*callback)(ObserverResult<T>))
+  {}
+
+  /*
+   * Updates the instruments aggregator with the new value. The labels should
+   * contain the keys and values to be associated with this value.
+   *
+   * @param value is the numerical representation of the metric being captured
+   * @param labels the set of labels, as key-value pairs
+   */
+  virtual void observe(T value, const common::KeyValueIterable &labels) override = 0;
+
+  /**
+   * Captures data by activating the callback function associated with the
+   * instrument and storing its return value.  Callbacks for asynchronous
+   * instruments are defined during construction.
+   *
+   * @param none
+   * @return none
+   */
+  virtual void run() override = 0;
+};
+
+template <class T>
+class SumObserver : virtual public AsynchronousInstrument<T>
+{
+
+public:
+  SumObserver() = default;
+
+  SumObserver(nostd::string_view name,
+              nostd::string_view description,
+              nostd::string_view unit,
+              bool enabled,
+              void (*callback)(ObserverResult<T>))
+  {}
+
+  virtual void observe(T value, const common::KeyValueIterable &labels) override = 0;
+
+  virtual void run() override = 0;
+};
+
+template <class T>
+class UpDownSumObserver : virtual public AsynchronousInstrument<T>
+{
+
+public:
+  UpDownSumObserver() = default;
+
+  UpDownSumObserver(nostd::string_view name,
+                    nostd::string_view description,
+                    nostd::string_view unit,
+                    bool enabled,
+                    void (*callback)(ObserverResult<T>))
+  {}
+
+  virtual void observe(T value, const common::KeyValueIterable &labels) override = 0;
+
+  virtual void run() override = 0;
+};
+
+}  // namespace metrics
+OPENTELEMETRY_END_NAMESPACE
+#endif
--- a/api/include/opentelemetry/_metrics/instrument.h
+++ b/api/include/opentelemetry/_metrics/instrument.h
@ -0,0 +1,209 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+#ifdef ENABLE_METRICS_PREVIEW
+
+#  include <iostream>
+#  include "opentelemetry/common/attribute_value.h"
+#  include "opentelemetry/common/key_value_iterable_view.h"
+#  include "opentelemetry/nostd/shared_ptr.h"
+#  include "opentelemetry/nostd/string_view.h"
+
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace metrics
+{
+
+// Enum classes to help determine instrument types in other parts of the API
+enum class InstrumentKind
+{
+  Counter           = 0,
+  UpDownCounter     = 1,
+  ValueRecorder     = 2,
+  ValueObserver     = 3,
+  SumObserver       = 4,
+  UpDownSumObserver = 5,
+};
+
+class Instrument
+{
+
+public:
+  // Note that Instruments should be created using the Meter class.
+  // Please refer to meter.h for documentation.
+  Instrument() = default;
+
+  /**
+   * Base class constructor for all other instrument types.  Whether or not
+   * an instrument is synchronous or bound, it requires a name, description,
+   * unit, and enabled flag.
+   *
+   * @param name is the identifier of the instrumenting library
+   * @param description explains what the metric captures
+   * @param unit specifies the data type held in the instrument
+   * @param enabled determines if the metric is currently capturing data
+   * @return Instrument type with the specified attributes
+   */
+  Instrument(nostd::string_view name,
+             nostd::string_view description,
+             nostd::string_view unit,
+             bool enabled)
+  {}
+
+  // Returns true if the instrument is enabled and collecting data
+  virtual bool IsEnabled() = 0;
+
+  // Return the instrument name
+  virtual nostd::string_view GetName() = 0;
+
+  // Return the instrument description
+  virtual nostd::string_view GetDescription() = 0;
+
+  // Return the insrument's units of measurement
+  virtual nostd::string_view GetUnits() = 0;
+
+  // Return the intrument's kind
+  virtual InstrumentKind GetKind() = 0;
+
+  virtual ~Instrument() = default;
+};
+
+template <class T>
+class BoundSynchronousInstrument : virtual public Instrument
+{
+
+public:
+  BoundSynchronousInstrument() = default;
+
+  BoundSynchronousInstrument(nostd::string_view name,
+                             nostd::string_view description,
+                             nostd::string_view unit,
+                             bool enabled);
+
+  /**
+   * Frees the resources associated with this Bound Instrument.
+   * The Metric from which this instrument was created is not impacted.
+   *
+   * @param none
+   * @return void
+   */
+  virtual void unbind() {}
+
+  /**
+   * Incremements the reference count of this bound object when a new instance is
+   * either created or the same instance is returned as a result of binding
+   *
+   * @param none
+   * @return void
+   */
+  virtual void inc_ref() {}
+
+  /**
+   * Return the object's current reference count.  This information is used to remove
+   * stale objects from instrument registries.
+   */
+  virtual int get_ref() { return 0; }
+
+  /**
+   * Records a single synchronous metric event; a call to the aggregator
+   * Since this is a bound synchronous instrument, labels are not required in  * metric capture
+   * calls.
+   *
+   * @param value is the numerical representation of the metric being captured
+   * @return void
+   */
+  virtual void update(T value) {}
+};
+
+template <class T>
+class SynchronousInstrument : virtual public Instrument
+{
+
+public:
+  SynchronousInstrument() = default;
+
+  SynchronousInstrument(nostd::string_view name,
+                        nostd::string_view description,
+                        nostd::string_view unit,
+                        bool enabled)
+  {}
+
+  /**
+   * Returns a Bound Instrument associated with the specified labels.         * Multiples requests
+   * with the same set of labels may return the same Bound Instrument instance.
+   *
+   * It is recommended that callers keep a reference to the Bound Instrument
+   * instead of repeatedly calling this operation.
+   *
+   * @param labels the set of labels, as key-value pairs
+   * @return a Bound Instrument
+   */
+  virtual nostd::shared_ptr<BoundSynchronousInstrument<T>> bind(
+      const common::KeyValueIterable &labels)
+  {
+    return nostd::shared_ptr<BoundSynchronousInstrument<T>>();
+  }
+
+  /**
+   * Records a single synchronous metric event.
+   * Since this is an unbound synchronous instrument, labels are required in  * metric capture
+   * calls.
+   *
+   * update can be used in instruments with both add or record since it simply
+   * activated the aggregator
+   *
+   * @param labels the set of labels, as key-value pairs
+   * @param value is the numerical representation of the metric being captured
+   * @return void
+   */
+  virtual void update(T value, const common::KeyValueIterable &labels) = 0;
+};
+
+template <class T>
+class ObserverResult;
+
+template <class T>
+class AsynchronousInstrument : virtual public Instrument
+{
+
+public:
+  AsynchronousInstrument() = default;
+
+  AsynchronousInstrument(nostd::string_view name,
+                         nostd::string_view description,
+                         nostd::string_view unit,
+                         bool enabled,
+                         void(callback)(ObserverResult<T>))
+  {}
+
+  /**
+   * Captures data through a manual call rather than the automatic collection process instituted
+   * in the run function.  Asynchronous instruments are generally expected to obtain data from
+   * their callbacks rather than direct calls.  This function is used by the callback to store data.
+   *
+   * @param value is the numerical representation of the metric being captured
+   * @param labels is the numerical representation of the metric being captured
+   * @return none
+   */
+  virtual void observe(T value, const common::KeyValueIterable &labels) = 0;
+
+  /**
+   * Captures data by activating the callback function associated with the
+   * instrument and storing its return value.  Callbacks for asynchronous
+   * instruments are defined during construction.
+   *
+   * @param none
+   * @return none
+   */
+  virtual void run() = 0;
+
+protected:
+  // Callback function which takes a pointer to an Asynchronous instrument (this) type which is
+  // stored in an observer result type and returns nothing.  This function calls the instrument's
+  // observe.
+  void (*callback_)(ObserverResult<T>);
+};
+
+}  // namespace metrics
+OPENTELEMETRY_END_NAMESPACE
+#endif
--- a/api/include/opentelemetry/_metrics/meter.h
+++ b/api/include/opentelemetry/_metrics/meter.h
@ -0,0 +1,288 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+#ifdef ENABLE_METRICS_PREVIEW
+
+#  include "opentelemetry/_metrics/async_instruments.h"
+#  include "opentelemetry/_metrics/instrument.h"
+#  include "opentelemetry/_metrics/sync_instruments.h"
+#  include "opentelemetry/nostd/shared_ptr.h"
+#  include "opentelemetry/nostd/span.h"
+#  include "opentelemetry/nostd/string_view.h"
+#  include "opentelemetry/version.h"
+
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace metrics
+{
+/**
+ * Handles instrument creation and provides a facility for batch recording.
+ *
+ * This class provides methods to create new metric instruments, record a
+ * batch of values to a specified set of instruments, and collect
+ * measurements from all instruments.
+ *
+ */
+class Meter
+{
+public:
+  virtual ~Meter() = default;
+
+  /**
+   * Creates a Counter with the passed characteristics and returns a shared_ptr to that Counter.
+   *
+   * @param name the name of the new Counter.
+   * @param description a brief description of what the Counter is used for.
+   * @param unit the unit of metric values following https://unitsofmeasure.org/ucum.html.
+   * @param enabled a boolean value that turns on or off the metric instrument.
+   * @return a shared pointer to the created Counter.
+   * @throws NullPointerException if {@code name} is null
+   * @throws IllegalArgumentException if a different metric by the same name exists in this meter.
+   * @throws IllegalArgumentException if the {@code name} does not match spec requirements.
+   */
+  virtual nostd::shared_ptr<Counter<short>> NewShortCounter(nostd::string_view name,
+                                                            nostd::string_view description,
+                                                            nostd::string_view unit,
+                                                            const bool enabled) = 0;
+
+  virtual nostd::shared_ptr<Counter<int>> NewIntCounter(nostd::string_view name,
+                                                        nostd::string_view description,
+                                                        nostd::string_view unit,
+                                                        const bool enabled) = 0;
+
+  virtual nostd::shared_ptr<Counter<float>> NewFloatCounter(nostd::string_view name,
+                                                            nostd::string_view description,
+                                                            nostd::string_view unit,
+                                                            const bool enabled) = 0;
+
+  virtual nostd::shared_ptr<Counter<double>> NewDoubleCounter(nostd::string_view name,
+                                                              nostd::string_view description,
+                                                              nostd::string_view unit,
+                                                              const bool enabled) = 0;
+
+  /**
+   * Creates an UpDownCounter with the passed characteristics and returns a shared_ptr to that
+   * UpDownCounter.
+   *
+   * @param name the name of the new UpDownCounter.
+   * @param description a brief description of what the UpDownCounter is used for.
+   * @param unit the unit of metric values following https://unitsofmeasure.org/ucum.html.
+   * @param enabled a boolean value that turns on or off the metric instrument.
+   * @return a shared pointer to the created UpDownCounter.
+   * @throws NullPointerException if {@code name} is null
+   * @throws IllegalArgumentException if a different metric by the same name exists in this meter.
+   * @throws IllegalArgumentException if the {@code name} does not match spec requirements.
+   */
+  virtual nostd::shared_ptr<UpDownCounter<short>> NewShortUpDownCounter(
+      nostd::string_view name,
+      nostd::string_view description,
+      nostd::string_view unit,
+      const bool enabled) = 0;
+
+  virtual nostd::shared_ptr<UpDownCounter<int>> NewIntUpDownCounter(nostd::string_view name,
+                                                                    nostd::string_view description,
+                                                                    nostd::string_view unit,
+                                                                    const bool enabled) = 0;
+
+  virtual nostd::shared_ptr<UpDownCounter<float>> NewFloatUpDownCounter(
+      nostd::string_view name,
+      nostd::string_view description,
+      nostd::string_view unit,
+      const bool enabled) = 0;
+
+  virtual nostd::shared_ptr<UpDownCounter<double>> NewDoubleUpDownCounter(
+      nostd::string_view name,
+      nostd::string_view description,
+      nostd::string_view unit,
+      const bool enabled) = 0;
+
+  /**
+   * Creates a ValueRecorder with the passed characteristics and returns a shared_ptr to that
+   * ValueRecorder.
+   *
+   * @param name the name of the new ValueRecorder.
+   * @param description a brief description of what the ValueRecorder is used for.
+   * @param unit the unit of metric values following https://unitsofmeasure.org/ucum.html.
+   * @param enabled a boolean value that turns on or off the metric instrument.
+   * @return a shared pointer to the created DoubleValueRecorder.
+   * @throws NullPointerException if {@code name} is null
+   * @throws IllegalArgumentException if a different metric by the same name exists in this meter.
+   * @throws IllegalArgumentException if the {@code name} does not match spec requirements.
+   */
+  virtual nostd::shared_ptr<ValueRecorder<short>> NewShortValueRecorder(
+      nostd::string_view name,
+      nostd::string_view description,
+      nostd::string_view unit,
+      const bool enabled) = 0;
+
+  virtual nostd::shared_ptr<ValueRecorder<int>> NewIntValueRecorder(nostd::string_view name,
+                                                                    nostd::string_view description,
+                                                                    nostd::string_view unit,
+                                                                    const bool enabled) = 0;
+
+  virtual nostd::shared_ptr<ValueRecorder<float>> NewFloatValueRecorder(
+      nostd::string_view name,
+      nostd::string_view description,
+      nostd::string_view unit,
+      const bool enabled) = 0;
+
+  virtual nostd::shared_ptr<ValueRecorder<double>> NewDoubleValueRecorder(
+      nostd::string_view name,
+      nostd::string_view description,
+      nostd::string_view unit,
+      const bool enabled) = 0;
+
+  /**
+   * Creates a SumObserver with the passed characteristics and returns a shared_ptr to that
+   * SumObserver.
+   *
+   * @param name the name of the new SumObserver.
+   * @param description a brief description of what the SumObserver is used for.
+   * @param unit the unit of metric values following https://unitsofmeasure.org/ucum.html.
+   * @param enabled a boolean value that turns on or off the metric instrument.
+   * @param callback the function to be observed by the instrument.
+   * @return a shared pointer to the created SumObserver.
+   * @throws NullPointerException if {@code name} is null
+   * @throws IllegalArgumentException if a different metric by the same name exists in this meter.
+   * @throws IllegalArgumentException if the {@code name} does not match spec requirements.
+   */
+  virtual nostd::shared_ptr<SumObserver<short>> NewShortSumObserver(
+      nostd::string_view name,
+      nostd::string_view description,
+      nostd::string_view unit,
+      const bool enabled,
+      void (*callback)(ObserverResult<short>)) = 0;
+
+  virtual nostd::shared_ptr<SumObserver<int>> NewIntSumObserver(
+      nostd::string_view name,
+      nostd::string_view description,
+      nostd::string_view unit,
+      const bool enabled,
+      void (*callback)(ObserverResult<int>)) = 0;
+
+  virtual nostd::shared_ptr<SumObserver<float>> NewFloatSumObserver(
+      nostd::string_view name,
+      nostd::string_view description,
+      nostd::string_view unit,
+      const bool enabled,
+      void (*callback)(ObserverResult<float>)) = 0;
+
+  virtual nostd::shared_ptr<SumObserver<double>> NewDoubleSumObserver(
+      nostd::string_view name,
+      nostd::string_view description,
+      nostd::string_view unit,
+      const bool enabled,
+      void (*callback)(ObserverResult<double>)) = 0;
+
+  /**
+   * Creates an UpDownSumObserver with the passed characteristics and returns a shared_ptr to
+   * that UpDowNSumObserver.
+   *
+   * @param name the name of the new UpDownSumObserver.
+   * @param description a brief description of what the UpDownSumObserver is used for.
+   * @param unit the unit of metric values following https://unitsofmeasure.org/ucum.html.
+   * @param enabled a boolean value that turns on or off the metric instrument.
+   * @param callback the function to be observed by the instrument.
+   * @return a shared pointer to the created UpDownSumObserver.
+   * @throws NullPointerException if {@code name} is null
+   * @throws IllegalArgumentException if a different metric by the same name exists in this meter.
+   * @throws IllegalArgumentException if the {@code name} does not match spec requirements.
+   */
+  virtual nostd::shared_ptr<UpDownSumObserver<short>> NewShortUpDownSumObserver(
+      nostd::string_view name,
+      nostd::string_view description,
+      nostd::string_view unit,
+      const bool enabled,
+      void (*callback)(ObserverResult<short>)) = 0;
+
+  virtual nostd::shared_ptr<UpDownSumObserver<int>> NewIntUpDownSumObserver(
+      nostd::string_view name,
+      nostd::string_view description,
+      nostd::string_view unit,
+      const bool enabled,
+      void (*callback)(ObserverResult<int>)) = 0;
+
+  virtual nostd::shared_ptr<UpDownSumObserver<float>> NewFloatUpDownSumObserver(
+      nostd::string_view name,
+      nostd::string_view description,
+      nostd::string_view unit,
+      const bool enabled,
+      void (*callback)(ObserverResult<float>)) = 0;
+
+  virtual nostd::shared_ptr<UpDownSumObserver<double>> NewDoubleUpDownSumObserver(
+      nostd::string_view name,
+      nostd::string_view description,
+      nostd::string_view unit,
+      const bool enabled,
+      void (*callback)(ObserverResult<double>)) = 0;
+
+  /**
+   * Creates a ValueObserver with the passed characteristics and returns a shared_ptr to that
+   * ValueObserver.
+   *
+   * @param name the name of the new ValueObserver.
+   * @param description a brief description of what the ValueObserver is used for.
+   * @param unit the unit of metric values following https://unitsofmeasure.org/ucum.html.
+   * @param enabled a boolean value that turns on or off the metric instrument.
+   * @param callback the function to be observed by the instrument.
+   * @return a shared pointer to the created ValueObserver.
+   * @throws NullPointerException if {@code name} is null
+   * @throws IllegalArgumentException if a different metric by the same name exists in this meter.
+   * @throws IllegalArgumentException if the {@code name} does not match spec requirements.
+   */
+  virtual nostd::shared_ptr<ValueObserver<short>> NewShortValueObserver(
+      nostd::string_view name,
+      nostd::string_view description,
+      nostd::string_view unit,
+      const bool enabled,
+      void (*callback)(ObserverResult<short>)) = 0;
+
+  virtual nostd::shared_ptr<ValueObserver<int>> NewIntValueObserver(
+      nostd::string_view name,
+      nostd::string_view description,
+      nostd::string_view unit,
+      const bool enabled,
+      void (*callback)(ObserverResult<int>)) = 0;
+
+  virtual nostd::shared_ptr<ValueObserver<float>> NewFloatValueObserver(
+      nostd::string_view name,
+      nostd::string_view description,
+      nostd::string_view unit,
+      const bool enabled,
+      void (*callback)(ObserverResult<float>)) = 0;
+
+  virtual nostd::shared_ptr<ValueObserver<double>> NewDoubleValueObserver(
+      nostd::string_view name,
+      nostd::string_view description,
+      nostd::string_view unit,
+      const bool enabled,
+      void (*callback)(ObserverResult<double>)) = 0;
+
+  /**
+   * Utility method that allows users to atomically record measurements to a set of
+   * synchronous metric instruments with a common set of labels.
+   *
+   * @param labels the set of labels to associate with this recorder.
+   * @param instruments a span of pointers to the instruments to record to.
+   * @param values a span of values to record to the instruments in the corresponding
+   * position in the instruments span.
+   */
+  virtual void RecordShortBatch(const common::KeyValueIterable &labels,
+                                nostd::span<SynchronousInstrument<short> *> instruments,
+                                nostd::span<const short> values) noexcept = 0;
+
+  virtual void RecordIntBatch(const common::KeyValueIterable &labels,
+                              nostd::span<SynchronousInstrument<int> *> instruments,
+                              nostd::span<const int> values) noexcept = 0;
+
+  virtual void RecordFloatBatch(const common::KeyValueIterable &labels,
+                                nostd::span<SynchronousInstrument<float> *> instruments,
+                                nostd::span<const float> values) noexcept = 0;
+
+  virtual void RecordDoubleBatch(const common::KeyValueIterable &labels,
+                                 nostd::span<SynchronousInstrument<double> *> instruments,
+                                 nostd::span<const double> values) noexcept = 0;
+};
+}  // namespace metrics
+OPENTELEMETRY_END_NAMESPACE
+#endif
--- a/api/include/opentelemetry/_metrics/meter_provider.h
+++ b/api/include/opentelemetry/_metrics/meter_provider.h
@ -0,0 +1,32 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+#ifdef ENABLE_METRICS_PREVIEW
+
+#  include "opentelemetry/_metrics/meter.h"
+#  include "opentelemetry/nostd/shared_ptr.h"
+#  include "opentelemetry/nostd/string_view.h"
+
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace metrics
+{
+/**
+ * Creates new Meter instances.
+ */
+class MeterProvider
+{
+public:
+  virtual ~MeterProvider() = default;
+  /**
+   * Gets or creates a named Meter instance.
+   *
+   * Optionally a version can be passed to create a named and versioned Meter
+   * instance.
+   */
+  virtual nostd::shared_ptr<Meter> GetMeter(nostd::string_view library_name,
+                                            nostd::string_view library_version = "") = 0;
+};
+}  // namespace metrics
+OPENTELEMETRY_END_NAMESPACE
+#endif
--- a/api/include/opentelemetry/_metrics/noop.h
+++ b/api/include/opentelemetry/_metrics/noop.h
@ -0,0 +1,654 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+#ifdef ENABLE_METRICS_PREVIEW
+// Please refer to provider.h for documentation on how to obtain a Meter object.
+//
+// This file is part of the internal implementation of OpenTelemetry. Nothing in this file should be
+// used directly. Please refer to meter.h for documentation on these interfaces.
+
+#  include "opentelemetry/_metrics/async_instruments.h"
+#  include "opentelemetry/_metrics/instrument.h"
+#  include "opentelemetry/_metrics/meter.h"
+#  include "opentelemetry/_metrics/meter_provider.h"
+#  include "opentelemetry/_metrics/sync_instruments.h"
+#  include "opentelemetry/nostd/string_view.h"
+#  include "opentelemetry/nostd/unique_ptr.h"
+#  include "opentelemetry/version.h"
+
+#  include <memory>
+
+// TODO: Create generic short pattern for opentelemetry::common and opentelemetry::trace and others
+// as necessary
+
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace metrics
+{
+template <class T>
+class NoopValueObserver : public ValueObserver<T>
+{
+
+public:
+  NoopValueObserver(nostd::string_view /*name*/,
+                    nostd::string_view /*description*/,
+                    nostd::string_view /*unit*/,
+                    bool /*enabled*/,
+                    void (*callback)(ObserverResult<T>))
+  {}
+
+  virtual bool IsEnabled() override { return false; }
+
+  virtual nostd::string_view GetName() override { return nostd::string_view(""); }
+
+  virtual nostd::string_view GetDescription() override { return nostd::string_view(""); }
+
+  virtual nostd::string_view GetUnits() override { return nostd::string_view(""); }
+
+  virtual void observe(T value, const common::KeyValueIterable &labels) override {}
+
+  virtual void run() override {}
+
+  virtual InstrumentKind GetKind() override { return InstrumentKind::Counter; }
+};
+
+template <class T>
+class NoopSumObserver : public SumObserver<T>
+{
+
+public:
+  NoopSumObserver(nostd::string_view /*name*/,
+                  nostd::string_view /*description*/,
+                  nostd::string_view /*unit*/,
+                  bool /*enabled*/,
+                  void (*callback)(ObserverResult<T>))
+  {}
+
+  virtual bool IsEnabled() override { return false; }
+
+  virtual nostd::string_view GetName() override { return nostd::string_view(""); }
+
+  virtual nostd::string_view GetDescription() override { return nostd::string_view(""); }
+
+  virtual nostd::string_view GetUnits() override { return nostd::string_view(""); }
+
+  virtual void observe(T value, const common::KeyValueIterable &labels) override {}
+
+  virtual void run() override {}
+
+  virtual InstrumentKind GetKind() override { return InstrumentKind::Counter; }
+};
+
+template <class T>
+class NoopUpDownSumObserver : public UpDownSumObserver<T>
+{
+
+public:
+  NoopUpDownSumObserver(nostd::string_view /*name*/,
+                        nostd::string_view /*description*/,
+                        nostd::string_view /*unit*/,
+                        bool /*enabled*/,
+                        void (*callback)(ObserverResult<T>))
+  {}
+
+  virtual bool IsEnabled() override { return false; }
+
+  virtual nostd::string_view GetName() override { return nostd::string_view(""); }
+
+  virtual nostd::string_view GetDescription() override { return nostd::string_view(""); }
+
+  virtual nostd::string_view GetUnits() override { return nostd::string_view(""); }
+
+  virtual void observe(T value, const common::KeyValueIterable &labels) override {}
+
+  virtual void run() override {}
+
+  virtual InstrumentKind GetKind() override { return InstrumentKind::Counter; }
+};
+
+template <class T>
+class BoundNoopCounter : public BoundCounter<T>
+{
+
+public:
+  BoundNoopCounter() = default;
+
+  BoundNoopCounter(nostd::string_view /*name*/,
+                   nostd::string_view /*description*/,
+                   nostd::string_view /*unit*/,
+                   bool /*enabled*/)
+  {}
+
+  virtual void add(T value) override {}
+
+  virtual bool IsEnabled() override { return false; }
+
+  virtual nostd::string_view GetName() override { return nostd::string_view(""); }
+
+  virtual nostd::string_view GetDescription() override { return nostd::string_view(""); }
+
+  virtual nostd::string_view GetUnits() override { return nostd::string_view(""); }
+
+  virtual InstrumentKind GetKind() override { return InstrumentKind::Counter; }
+};
+
+template <class T>
+class NoopCounter : public Counter<T>
+{
+
+public:
+  NoopCounter() = default;
+
+  NoopCounter(nostd::string_view /*name*/,
+              nostd::string_view /*description*/,
+              nostd::string_view /*unit*/,
+              bool /*enabled*/)
+  {}
+
+  nostd::shared_ptr<BoundNoopCounter<T>> bindNoopCounter(
+      const common::KeyValueIterable & /*labels*/)
+  {
+    return nostd::shared_ptr<BoundNoopCounter<T>>(new BoundNoopCounter<T>());
+  }
+
+  virtual void add(T value, const common::KeyValueIterable & /*labels*/) override {}
+
+  virtual void update(T value, const common::KeyValueIterable & /*labels*/) override {}
+
+  virtual bool IsEnabled() override { return false; }
+
+  virtual nostd::string_view GetName() override { return nostd::string_view(""); }
+
+  virtual nostd::string_view GetDescription() override { return nostd::string_view(""); }
+
+  virtual nostd::string_view GetUnits() override { return nostd::string_view(""); }
+
+  virtual InstrumentKind GetKind() override { return InstrumentKind::Counter; }
+};
+
+template <class T>
+class BoundNoopUpDownCounter : public BoundUpDownCounter<T>
+{
+
+public:
+  BoundNoopUpDownCounter() = default;
+
+  BoundNoopUpDownCounter(nostd::string_view /*name*/,
+                         nostd::string_view /*description*/,
+                         nostd::string_view /*unit*/,
+                         bool /*enabled*/)
+  {}
+
+  virtual void add(T value) override {}
+
+  virtual bool IsEnabled() override { return false; }
+
+  virtual nostd::string_view GetName() override { return nostd::string_view(""); }
+
+  virtual nostd::string_view GetDescription() override { return nostd::string_view(""); }
+
+  virtual nostd::string_view GetUnits() override { return nostd::string_view(""); }
+
+  virtual InstrumentKind GetKind() override { return InstrumentKind::UpDownCounter; }
+};
+
+template <class T>
+class NoopUpDownCounter : public UpDownCounter<T>
+{
+
+public:
+  NoopUpDownCounter() = default;
+
+  NoopUpDownCounter(nostd::string_view /*name*/,
+                    nostd::string_view /*description*/,
+                    nostd::string_view /*unit*/,
+                    bool /*enabled*/)
+  {}
+
+  nostd::shared_ptr<BoundNoopUpDownCounter<T>> bindNoopUpDownCounter(
+      const common::KeyValueIterable & /*labels*/)
+  {
+    return nostd::shared_ptr<BoundNoopUpDownCounter<T>>(new BoundNoopUpDownCounter<T>());
+  }
+
+  virtual void add(T value, const common::KeyValueIterable & /*labels*/) override {}
+
+  virtual void update(T value, const common::KeyValueIterable & /*labels*/) override {}
+
+  virtual bool IsEnabled() override { return false; }
+
+  virtual nostd::string_view GetName() override { return nostd::string_view(""); }
+
+  virtual nostd::string_view GetDescription() override { return nostd::string_view(""); }
+
+  virtual nostd::string_view GetUnits() override { return nostd::string_view(""); }
+
+  virtual InstrumentKind GetKind() override { return InstrumentKind::UpDownCounter; }
+};
+
+template <class T>
+class BoundNoopValueRecorder : public BoundValueRecorder<T>
+{
+
+public:
+  BoundNoopValueRecorder() = default;
+
+  BoundNoopValueRecorder(nostd::string_view /*name*/,
+                         nostd::string_view /*description*/,
+                         nostd::string_view /*unit*/,
+                         bool /*enabled*/)
+  {}
+
+  virtual void record(T value) override {}
+
+  virtual bool IsEnabled() override { return false; }
+
+  virtual nostd::string_view GetName() override { return nostd::string_view(""); }
+
+  virtual nostd::string_view GetDescription() override { return nostd::string_view(""); }
+
+  virtual nostd::string_view GetUnits() override { return nostd::string_view(""); }
+
+  virtual InstrumentKind GetKind() override { return InstrumentKind::ValueRecorder; }
+};
+
+template <class T>
+class NoopValueRecorder : public ValueRecorder<T>
+{
+
+public:
+  NoopValueRecorder() = default;
+
+  NoopValueRecorder(nostd::string_view /*name*/,
+                    nostd::string_view /*description*/,
+                    nostd::string_view /*unit*/,
+                    bool /*enabled*/)
+  {}
+
+  nostd::shared_ptr<BoundNoopValueRecorder<T>> bindNoopValueRecorder(
+      const common::KeyValueIterable & /*labels*/)
+  {
+    return nostd::shared_ptr<BoundNoopValueRecorder<T>>(new BoundNoopValueRecorder<T>());
+  }
+
+  virtual void record(T value, const common::KeyValueIterable & /*labels*/) override {}
+
+  virtual void update(T value, const common::KeyValueIterable & /*labels*/) override {}
+
+  virtual bool IsEnabled() override { return false; }
+
+  virtual nostd::string_view GetName() override { return nostd::string_view(""); }
+
+  virtual nostd::string_view GetDescription() override { return nostd::string_view(""); }
+
+  virtual nostd::string_view GetUnits() override { return nostd::string_view(""); }
+
+  virtual InstrumentKind GetKind() override { return InstrumentKind::ValueRecorder; }
+};
+
+/**
+ * No-op implementation of Meter. This class should not be used directly.
+ */
+class NoopMeter : public Meter
+{
+public:
+  NoopMeter() = default;
+
+  /**
+   *
+   * Creates a new NoopCounter<T> and returns a shared ptr to that counter.
+   *
+   * @param name the name of the instrument.
+   * @param description a brief description of the instrument.
+   * @param unit the unit of metric values following https://unitsofmeasure.org/ucum.html.
+   * @param enabled a boolean that turns the metric instrument on and off.
+   * @return
+   */
+  nostd::shared_ptr<Counter<short>> NewShortCounter(nostd::string_view name,
+                                                    nostd::string_view description,
+                                                    nostd::string_view unit,
+                                                    const bool enabled) override
+  {
+    return nostd::shared_ptr<Counter<short>>{
+        new NoopCounter<short>(name, description, unit, enabled)};
+  }
+
+  nostd::shared_ptr<Counter<int>> NewIntCounter(nostd::string_view name,
+                                                nostd::string_view description,
+                                                nostd::string_view unit,
+                                                const bool enabled) override
+  {
+    return nostd::shared_ptr<Counter<int>>{new NoopCounter<int>(name, description, unit, enabled)};
+  }
+
+  nostd::shared_ptr<Counter<float>> NewFloatCounter(nostd::string_view name,
+                                                    nostd::string_view description,
+                                                    nostd::string_view unit,
+                                                    const bool enabled) override
+  {
+    return nostd::shared_ptr<Counter<float>>{
+        new NoopCounter<float>(name, description, unit, enabled)};
+  }
+
+  nostd::shared_ptr<Counter<double>> NewDoubleCounter(nostd::string_view name,
+                                                      nostd::string_view description,
+                                                      nostd::string_view unit,
+                                                      const bool enabled) override
+  {
+    return nostd::shared_ptr<Counter<double>>{
+        new NoopCounter<double>(name, description, unit, enabled)};
+  }
+
+  /**
+   *
+   * Creates a new NoopCounter<T> and returns a shared ptr to that counter.
+   *
+   * @param name the name of the instrument.
+   * @param description a brief description of the instrument.
+   * @param unit the unit of metric values following https://unitsofmeasure.org/ucum.html.
+   * @param enabled a boolean that turns the metric instrument on and off.
+   * @return
+   */
+  nostd::shared_ptr<UpDownCounter<short>> NewShortUpDownCounter(nostd::string_view name,
+                                                                nostd::string_view description,
+                                                                nostd::string_view unit,
+                                                                const bool enabled) override
+  {
+    return nostd::shared_ptr<UpDownCounter<short>>{
+        new NoopUpDownCounter<short>(name, description, unit, enabled)};
+  }
+
+  nostd::shared_ptr<UpDownCounter<int>> NewIntUpDownCounter(nostd::string_view name,
+                                                            nostd::string_view description,
+                                                            nostd::string_view unit,
+                                                            const bool enabled) override
+  {
+    return nostd::shared_ptr<UpDownCounter<int>>{
+        new NoopUpDownCounter<int>(name, description, unit, enabled)};
+  }
+
+  nostd::shared_ptr<UpDownCounter<float>> NewFloatUpDownCounter(nostd::string_view name,
+                                                                nostd::string_view description,
+                                                                nostd::string_view unit,
+                                                                const bool enabled) override
+  {
+    return nostd::shared_ptr<UpDownCounter<float>>{
+        new NoopUpDownCounter<float>(name, description, unit, enabled)};
+  }
+
+  nostd::shared_ptr<UpDownCounter<double>> NewDoubleUpDownCounter(nostd::string_view name,
+                                                                  nostd::string_view description,
+                                                                  nostd::string_view unit,
+                                                                  const bool enabled) override
+  {
+    return nostd::shared_ptr<UpDownCounter<double>>{
+        new NoopUpDownCounter<double>(name, description, unit, enabled)};
+  }
+
+  /**
+   *
+   * Creates a new ValueRecorder<T> and returns a shared ptr to that counter.
+   *
+   * @param name the name of the instrument.
+   * @param description a brief description of the instrument.
+   * @param unit the unit of metric values following https://unitsofmeasure.org/ucum.html.
+   * @param enabled a boolean that turns the metric instrument on and off.
+   * @return
+   */
+  nostd::shared_ptr<ValueRecorder<short>> NewShortValueRecorder(nostd::string_view name,
+                                                                nostd::string_view description,
+                                                                nostd::string_view unit,
+                                                                const bool enabled) override
+  {
+    return nostd::shared_ptr<ValueRecorder<short>>{
+        new NoopValueRecorder<short>(name, description, unit, enabled)};
+  }
+
+  nostd::shared_ptr<ValueRecorder<int>> NewIntValueRecorder(nostd::string_view name,
+                                                            nostd::string_view description,
+                                                            nostd::string_view unit,
+                                                            const bool enabled) override
+  {
+    return nostd::shared_ptr<ValueRecorder<int>>{
+        new NoopValueRecorder<int>(name, description, unit, enabled)};
+  }
+
+  nostd::shared_ptr<ValueRecorder<float>> NewFloatValueRecorder(nostd::string_view name,
+                                                                nostd::string_view description,
+                                                                nostd::string_view unit,
+                                                                const bool enabled) override
+  {
+    return nostd::shared_ptr<ValueRecorder<float>>{
+        new NoopValueRecorder<float>(name, description, unit, enabled)};
+  }
+
+  nostd::shared_ptr<ValueRecorder<double>> NewDoubleValueRecorder(nostd::string_view name,
+                                                                  nostd::string_view description,
+                                                                  nostd::string_view unit,
+                                                                  const bool enabled) override
+  {
+    return nostd::shared_ptr<ValueRecorder<double>>{
+        new NoopValueRecorder<double>(name, description, unit, enabled)};
+  }
+
+  /**
+   *
+   * Creates a new SumObserver<T> and returns a shared ptr to that counter.
+   *
+   * @param name the name of the instrument.
+   * @param description a brief description of the instrument.
+   * @param unit the unit of metric values following https://unitsofmeasure.org/ucum.html.
+   * @param enabled a boolean that turns the metric instrument on and off.
+   * @return
+   */
+  nostd::shared_ptr<SumObserver<short>> NewShortSumObserver(
+      nostd::string_view name,
+      nostd::string_view description,
+      nostd::string_view unit,
+      const bool enabled,
+      void (*callback)(ObserverResult<short>)) override
+  {
+    return nostd::shared_ptr<SumObserver<short>>{
+        new NoopSumObserver<short>(name, description, unit, enabled, callback)};
+  }
+
+  nostd::shared_ptr<SumObserver<int>> NewIntSumObserver(
+      nostd::string_view name,
+      nostd::string_view description,
+      nostd::string_view unit,
+      const bool enabled,
+      void (*callback)(ObserverResult<int>)) override
+  {
+    return nostd::shared_ptr<SumObserver<int>>{
+        new NoopSumObserver<int>(name, description, unit, enabled, callback)};
+  }
+
+  nostd::shared_ptr<SumObserver<float>> NewFloatSumObserver(
+      nostd::string_view name,
+      nostd::string_view description,
+      nostd::string_view unit,
+      const bool enabled,
+      void (*callback)(ObserverResult<float>)) override
+  {
+    return nostd::shared_ptr<SumObserver<float>>{
+        new NoopSumObserver<float>(name, description, unit, enabled, callback)};
+  }
+
+  nostd::shared_ptr<SumObserver<double>> NewDoubleSumObserver(
+      nostd::string_view name,
+      nostd::string_view description,
+      nostd::string_view unit,
+      const bool enabled,
+      void (*callback)(ObserverResult<double>)) override
+  {
+    return nostd::shared_ptr<SumObserver<double>>{
+        new NoopSumObserver<double>(name, description, unit, enabled, callback)};
+  }
+
+  /**
+   *
+   * Creates a new UpDownSumObserver<T> and returns a shared ptr to that counter.
+   *
+   * @param name the name of the instrument.
+   * @param description a brief description of the instrument.
+   * @param unit the unit of metric values following https://unitsofmeasure.org/ucum.html.
+   * @param enabled a boolean that turns the metric instrument on and off.
+   * @return
+   */
+  nostd::shared_ptr<UpDownSumObserver<short>> NewShortUpDownSumObserver(
+      nostd::string_view name,
+      nostd::string_view description,
+      nostd::string_view unit,
+      const bool enabled,
+      void (*callback)(ObserverResult<short>)) override
+  {
+    return nostd::shared_ptr<UpDownSumObserver<short>>{
+        new NoopUpDownSumObserver<short>(name, description, unit, enabled, callback)};
+  }
+
+  nostd::shared_ptr<UpDownSumObserver<int>> NewIntUpDownSumObserver(
+      nostd::string_view name,
+      nostd::string_view description,
+      nostd::string_view unit,
+      const bool enabled,
+      void (*callback)(ObserverResult<int>)) override
+  {
+    return nostd::shared_ptr<UpDownSumObserver<int>>{
+        new NoopUpDownSumObserver<int>(name, description, unit, enabled, callback)};
+  }
+
+  nostd::shared_ptr<UpDownSumObserver<float>> NewFloatUpDownSumObserver(
+      nostd::string_view name,
+      nostd::string_view description,
+      nostd::string_view unit,
+      const bool enabled,
+      void (*callback)(ObserverResult<float>)) override
+  {
+    return nostd::shared_ptr<UpDownSumObserver<float>>{
+        new NoopUpDownSumObserver<float>(name, description, unit, enabled, callback)};
+  }
+
+  nostd::shared_ptr<UpDownSumObserver<double>> NewDoubleUpDownSumObserver(
+      nostd::string_view name,
+      nostd::string_view description,
+      nostd::string_view unit,
+      const bool enabled,
+      void (*callback)(ObserverResult<double>)) override
+  {
+    return nostd::shared_ptr<UpDownSumObserver<double>>{
+        new NoopUpDownSumObserver<double>(name, description, unit, enabled, callback)};
+  }
+
+  /**
+   *
+   * Creates a new ValueObserverObserver<T> and returns a shared ptr to that counter.
+   *
+   * @param name the name of the instrument.
+   * @param description a brief description of the instrument.
+   * @param unit the unit of metric values following https://unitsofmeasure.org/ucum.html.
+   * @param enabled a boolean that turns the metric instrument on and off.
+   * @return
+   */
+  nostd::shared_ptr<ValueObserver<short>> NewShortValueObserver(
+      nostd::string_view name,
+      nostd::string_view description,
+      nostd::string_view unit,
+      const bool enabled,
+      void (*callback)(ObserverResult<short>)) override
+  {
+    return nostd::shared_ptr<ValueObserver<short>>{
+        new NoopValueObserver<short>(name, description, unit, enabled, callback)};
+  }
+
+  nostd::shared_ptr<ValueObserver<int>> NewIntValueObserver(
+      nostd::string_view name,
+      nostd::string_view description,
+      nostd::string_view unit,
+      const bool enabled,
+      void (*callback)(ObserverResult<int>)) override
+  {
+    return nostd::shared_ptr<ValueObserver<int>>{
+        new NoopValueObserver<int>(name, description, unit, enabled, callback)};
+  }
+
+  nostd::shared_ptr<ValueObserver<float>> NewFloatValueObserver(
+      nostd::string_view name,
+      nostd::string_view description,
+      nostd::string_view unit,
+      const bool enabled,
+      void (*callback)(ObserverResult<float>)) override
+  {
+    return nostd::shared_ptr<ValueObserver<float>>{
+        new NoopValueObserver<float>(name, description, unit, enabled, callback)};
+  }
+
+  nostd::shared_ptr<ValueObserver<double>> NewDoubleValueObserver(
+      nostd::string_view name,
+      nostd::string_view description,
+      nostd::string_view unit,
+      const bool enabled,
+      void (*callback)(ObserverResult<double>)) override
+  {
+    return nostd::shared_ptr<ValueObserver<double>>{
+        new NoopValueObserver<double>(name, description, unit, enabled, callback)};
+  }
+
+  /**
+   *
+   * Utility method that allows users to atomically record measurements to a set of
+   * synchronous metric instruments with a common set of labels.
+   *
+   * @param labels the set of labels to associate with this recorder.
+   * @param instrs the instruments to record to.
+   * @param values the value to record to those instruments.
+   */
+  void RecordShortBatch(const common::KeyValueIterable &labels,
+                        nostd::span<SynchronousInstrument<short> *> instruments,
+                        nostd::span<const short> values) noexcept override
+  {
+    // No-op
+  }
+
+  void RecordIntBatch(const common::KeyValueIterable &labels,
+                      nostd::span<SynchronousInstrument<int> *> instruments,
+                      nostd::span<const int> values) noexcept override
+  {
+    // No-op
+  }
+
+  void RecordFloatBatch(const common::KeyValueIterable &labels,
+                        nostd::span<SynchronousInstrument<float> *> instruments,
+                        nostd::span<const float> values) noexcept override
+  {
+    // No-op
+  }
+
+  void RecordDoubleBatch(const common::KeyValueIterable &labels,
+                         nostd::span<SynchronousInstrument<double> *> instruments,
+                         nostd::span<const double> values) noexcept override
+  {
+    // No-op
+  }
+};
+
+class NoopMeterProvider final : public opentelemetry::metrics::MeterProvider
+{
+public:
+  NoopMeterProvider()
+      : meter_{nostd::shared_ptr<opentelemetry::metrics::NoopMeter>(
+            new opentelemetry::metrics::NoopMeter)}
+  {}
+
+  nostd::shared_ptr<opentelemetry::metrics::Meter> GetMeter(
+      nostd::string_view library_name,
+      nostd::string_view library_version) override
+  {
+    return meter_;
+  }
+
+private:
+  nostd::shared_ptr<opentelemetry::metrics::Meter> meter_;
+};
+}  // namespace metrics
+OPENTELEMETRY_END_NAMESPACE
+#endif
--- a/api/include/opentelemetry/_metrics/observer_result.h
+++ b/api/include/opentelemetry/_metrics/observer_result.h
@ -0,0 +1,41 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+#ifdef ENABLE_METRICS_PREVIEW
+
+#  include "opentelemetry/_metrics/instrument.h"
+#  include "opentelemetry/nostd/shared_ptr.h"
+
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace metrics
+{
+
+/**
+ * ObserverResult class is necessary for the callback recording asynchronous
+ * instrument use.  Callback functions asynchronous instruments are designed to
+ * accept a single ObserverResult object and update using its pointer to the
+ * instrument itself.
+ */
+
+template <class T>
+class ObserverResult
+{
+
+public:
+  ObserverResult() = default;
+
+  ObserverResult(AsynchronousInstrument<T> *instrument) : instrument_(instrument) {}
+
+  virtual void observe(T value, const common::KeyValueIterable &labels)
+  {
+    instrument_->observe(value, labels);
+  }
+
+private:
+  AsynchronousInstrument<T> *instrument_;
+};
+
+}  // namespace metrics
+OPENTELEMETRY_END_NAMESPACE
+#endif
--- a/api/include/opentelemetry/_metrics/provider.h
+++ b/api/include/opentelemetry/_metrics/provider.h
@ -0,0 +1,59 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+#ifdef ENABLE_METRICS_PREVIEW
+#  include <mutex>
+
+#  include "opentelemetry/_metrics/meter_provider.h"
+#  include "opentelemetry/_metrics/noop.h"
+#  include "opentelemetry/common/spin_lock_mutex.h"
+#  include "opentelemetry/nostd/shared_ptr.h"
+
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace metrics
+{
+/**
+ * Stores the singleton global MeterProvider.
+ */
+class Provider
+{
+public:
+  /**
+   * Returns the singleton MeterProvider.
+   *
+   * By default, a no-op MeterProvider is returned. This will never return a
+   * nullptr MeterProvider.
+   */
+  static nostd::shared_ptr<MeterProvider> GetMeterProvider() noexcept
+  {
+    std::lock_guard<common::SpinLockMutex> guard(GetLock());
+    return nostd::shared_ptr<MeterProvider>(GetProvider());
+  }
+
+  /**
+   * Changes the singleton MeterProvider.
+   */
+  static void SetMeterProvider(nostd::shared_ptr<MeterProvider> tp) noexcept
+  {
+    std::lock_guard<common::SpinLockMutex> guard(GetLock());
+    GetProvider() = tp;
+  }
+
+private:
+  static nostd::shared_ptr<MeterProvider> &GetProvider() noexcept
+  {
+    static nostd::shared_ptr<MeterProvider> provider(new NoopMeterProvider);
+    return provider;
+  }
+
+  static common::SpinLockMutex &GetLock() noexcept
+  {
+    static common::SpinLockMutex lock;
+    return lock;
+  }
+};
+
+}  // namespace metrics
+OPENTELEMETRY_END_NAMESPACE
+#endif
--- a/api/include/opentelemetry/_metrics/sync_instruments.h
+++ b/api/include/opentelemetry/_metrics/sync_instruments.h
@ -0,0 +1,181 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+#ifdef ENABLE_METRICS_PREVIEW
+
+#  include "opentelemetry/_metrics/instrument.h"
+
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace metrics
+{
+
+template <class T>
+class BoundCounter : virtual public BoundSynchronousInstrument<T>
+{
+
+public:
+  BoundCounter() = default;
+
+  BoundCounter(nostd::string_view name,
+               nostd::string_view description,
+               nostd::string_view unit,
+               bool enabled);
+
+  /*
+   * Add adds the value to the counter's sum. The labels are already linked   * to the instrument
+   * and are not specified.
+   *
+   * @param value the numerical representation of the metric being captured
+   * @param labels the set of labels, as key-value pairs
+   */
+  virtual void add(T value) = 0;
+};
+
+template <class T>
+class Counter : virtual public SynchronousInstrument<T>
+{
+
+public:
+  Counter() = default;
+
+  Counter(nostd::string_view name,
+          nostd::string_view description,
+          nostd::string_view unit,
+          bool enabled)
+  {}
+
+  /*
+   * Bind creates a bound instrument for this counter. The labels are
+   * associated with values recorded via subsequent calls to Record.
+   *
+   * @param labels the set of labels, as key-value pairs.
+   * @return a BoundIntCounter tied to the specified labels
+   */
+  virtual nostd::shared_ptr<BoundCounter<T>> bindCounter(const common::KeyValueIterable &labels)
+  {
+    return nostd::shared_ptr<BoundCounter<T>>();
+  }
+
+  /*
+   * Add adds the value to the counter's sum. The labels should contain
+   * the keys and values to be associated with this value.  Counters only     * accept positive
+   * valued updates.
+   *
+   * @param value the numerical representation of the metric being captured
+   * @param labels the set of labels, as key-value pairs
+   */
+  virtual void add(T value, const common::KeyValueIterable &labels) = 0;
+
+  virtual void update(T value, const common::KeyValueIterable &labels) override = 0;
+};
+
+template <class T>
+class BoundUpDownCounter : virtual public BoundSynchronousInstrument<T>
+{
+
+public:
+  BoundUpDownCounter() = default;
+
+  BoundUpDownCounter(nostd::string_view name,
+                     nostd::string_view description,
+                     nostd::string_view unit,
+                     bool enabled);
+
+  /*
+   * Add adds the value to the counter's sum. The labels are already linked to * the instrument and
+   * do not need to specified again.  UpDownCounters can accept positive and negative values.
+   *
+   * @param value the numerical representation of the metric being captured
+   * @param labels the set of labels, as key-value pairs
+   */
+  virtual void add(T value) = 0;
+};
+
+template <class T>
+class UpDownCounter : virtual public SynchronousInstrument<T>
+{
+
+public:
+  UpDownCounter() = default;
+
+  UpDownCounter(nostd::string_view name,
+                nostd::string_view description,
+                nostd::string_view unit,
+                bool enabled);
+
+  virtual nostd::shared_ptr<BoundUpDownCounter<T>> bindUpDownCounter(
+      const common::KeyValueIterable &labels)
+  {
+    return nostd::shared_ptr<BoundUpDownCounter<T>>();
+  }
+
+  /*
+   * Add adds the value to the counter's sum. The labels should contain
+   * the keys and values to be associated with this value.  UpDownCounters can
+   * accept positive and negative values.
+   *
+   * @param value the numerical representation of the metric being captured
+   * @param labels the set of labels, as key-value pairs
+   */
+  virtual void add(T value, const common::KeyValueIterable &labels) = 0;
+
+  virtual void update(T value, const common::KeyValueIterable &labels) override = 0;
+};
+
+template <class T>
+class BoundValueRecorder : virtual public BoundSynchronousInstrument<T>
+{
+
+public:
+  BoundValueRecorder() = default;
+
+  BoundValueRecorder(nostd::string_view name,
+                     nostd::string_view description,
+                     nostd::string_view unit,
+                     bool enabled);
+
+  /*
+   * Records the value by summing it with previous measurements and checking  * previously stored
+   * minimum and maximum values. The labels associated with * new values are already linked to the
+   * instrument as it is bound.          * ValueRecorders can accept positive and negative values.
+   *
+   * @param value the numerical representation of the metric being captured
+   */
+  virtual void record(T value) = 0;
+};
+
+template <class T>
+class ValueRecorder : virtual public SynchronousInstrument<T>
+{
+
+public:
+  ValueRecorder() = default;
+
+  ValueRecorder(nostd::string_view name,
+                nostd::string_view description,
+                nostd::string_view unit,
+                bool enabled);
+
+  virtual nostd::shared_ptr<BoundValueRecorder<T>> bindValueRecorder(
+      const common::KeyValueIterable &labels)
+  {
+    return nostd::shared_ptr<BoundValueRecorder<T>>();
+  }
+
+  /*
+   * Records the value by summing it with previous measurements and checking  * previously stored
+   * minimum and maximum values. The labels should contain the keys and values to be associated with
+   * this value.  ValueRecorders can accept positive and negative values.
+   *
+   * @param value the numerical representation of the metric being captured
+   * @param labels the set of labels, as key-value pairs
+   */
+  virtual void record(T value, const common::KeyValueIterable &labels) = 0;
+
+  virtual void update(T value, const common::KeyValueIterable &labels) override = 0;
+};
+
+}  // namespace metrics
+OPENTELEMETRY_END_NAMESPACE
+#endif
--- a/api/include/opentelemetry/baggage/baggage.h
+++ b/api/include/opentelemetry/baggage/baggage.h
@ -1,4 +1,4 @@
-// Copyright The OpenTelemetry Authors
+// Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0

 #pragma once
@ -6,7 +6,6 @@
 #include <cctype>

 #include "opentelemetry/common/kv_properties.h"
-#include "opentelemetry/common/macros.h"
 #include "opentelemetry/nostd/shared_ptr.h"
 #include "opentelemetry/nostd/string_view.h"
 #include "opentelemetry/version.h"
@ -16,7 +15,7 @@ OPENTELEMETRY_BEGIN_NAMESPACE
 namespace baggage
 {

-class OPENTELEMETRY_EXPORT Baggage
+class Baggage
 {
 public:
  static constexpr size_t kMaxKeyValuePairs = 180;
@ -26,15 +25,15 @@ public:
  static constexpr char kMembersSeparator   = ',';
  static constexpr char kMetadataSeparator  = ';';

-  Baggage() noexcept : kv_properties_(new common::KeyValueProperties()) {}
-  Baggage(size_t size) noexcept : kv_properties_(new common::KeyValueProperties(size)) {}
+  Baggage() : kv_properties_(new opentelemetry::common::KeyValueProperties()) {}
+  Baggage(size_t size) : kv_properties_(new opentelemetry::common::KeyValueProperties(size)){};

  template <class T>
-  Baggage(const T &keys_and_values) noexcept
-      : kv_properties_(new common::KeyValueProperties(keys_and_values))
+  Baggage(const T &keys_and_values)
+      : kv_properties_(new opentelemetry::common::KeyValueProperties(keys_and_values))
  {}

-  OPENTELEMETRY_API_SINGLETON static nostd::shared_ptr<Baggage> GetDefault()
+  static nostd::shared_ptr<Baggage> GetDefault()
  {
    static nostd::shared_ptr<Baggage> baggage{new Baggage()};
    return baggage;
@ -43,7 +42,7 @@ public:
  /* Get value for key in the baggage
     @returns true if key is found, false otherwise
  */
-  bool GetValue(nostd::string_view key, std::string &value) const noexcept
+  bool GetValue(nostd::string_view key, std::string &value) const
  {
    return kv_properties_->GetValue(key, value);
  }
@ -51,8 +50,7 @@ public:
  /* Returns shared_ptr of new baggage object which contains new key-value pair. If key or value is
     invalid, copy of current baggage is returned
  */
-  nostd::shared_ptr<Baggage> Set(const nostd::string_view &key,
-                                 const nostd::string_view &value) noexcept
+  nostd::shared_ptr<Baggage> Set(const nostd::string_view &key, const nostd::string_view &value)
  {

    nostd::shared_ptr<Baggage> baggage(new Baggage(kv_properties_->Size() + 1));
@ -91,7 +89,7 @@ public:
  // if key does not exist, copy of current baggage is returned.
  // Validity of key is not checked as invalid keys should never be populated in baggage in the
  // first place.
-  nostd::shared_ptr<Baggage> Delete(nostd::string_view key) noexcept
+  nostd::shared_ptr<Baggage> Delete(nostd::string_view key)
  {
    // keeping size of baggage same as key might not be found in it
    nostd::shared_ptr<Baggage> baggage(new Baggage(kv_properties_->Size()));
@ -105,7 +103,7 @@ public:
  }

  // Returns shared_ptr of baggage after extracting key-value pairs from header
-  static nostd::shared_ptr<Baggage> FromHeader(nostd::string_view header) noexcept
+  static nostd::shared_ptr<Baggage> FromHeader(nostd::string_view header)
  {
    if (header.size() > kMaxSize)
    {
@ -160,7 +158,7 @@ public:
  }

  // Creates string from baggage object.
-  std::string ToHeader() const noexcept
+  std::string ToHeader() const
  {
    std::string header_s;
    bool first = true;
@ -251,9 +249,7 @@ private:
    };

    auto from_hex = [](char c) -> char {
-      // c - '0' produces integer type which could trigger error/warning when casting to char,
-      // but the cast is safe here.
-      return static_cast<char>(std::isdigit(c) ? c - '0' : std::toupper(c) - 'A' + 10);
+      return std::isdigit(c) ? c - '0' : std::toupper(c) - 'A' + 10;
    };

    std::string ret;
@ -291,7 +287,7 @@ private:

 private:
  // Store entries in a C-style array to avoid using std::array or std::vector.
-  nostd::unique_ptr<common::KeyValueProperties> kv_properties_;
+  nostd::unique_ptr<opentelemetry::common::KeyValueProperties> kv_properties_;
 };

 }  // namespace baggage
--- a/api/include/opentelemetry/baggage/baggage_context.h
+++ b/api/include/opentelemetry/baggage/baggage_context.h
@ -15,19 +15,21 @@ namespace baggage

 static const std::string kBaggageHeader = "baggage";

-inline nostd::shared_ptr<Baggage> GetBaggage(const context::Context &context) noexcept
+inline nostd::shared_ptr<opentelemetry::baggage::Baggage> GetBaggage(
+    const opentelemetry::context::Context &context)
 {
  context::ContextValue context_value = context.GetValue(kBaggageHeader);
-  if (nostd::holds_alternative<nostd::shared_ptr<Baggage>>(context_value))
+  if (nostd::holds_alternative<nostd::shared_ptr<opentelemetry::baggage::Baggage>>(context_value))
  {
-    return nostd::get<nostd::shared_ptr<Baggage>>(context_value);
+    return nostd::get<nostd::shared_ptr<opentelemetry::baggage::Baggage>>(context_value);
  }
-  static nostd::shared_ptr<Baggage> empty_baggage{new Baggage()};
+  static nostd::shared_ptr<opentelemetry::baggage::Baggage> empty_baggage{
+      new opentelemetry::baggage::Baggage()};
  return empty_baggage;
 }

-inline context::Context SetBaggage(context::Context &context,
-                                   const nostd::shared_ptr<Baggage> &baggage) noexcept
+inline context::Context SetBaggage(opentelemetry::context::Context &context,
+                                   nostd::shared_ptr<opentelemetry::baggage::Baggage> baggage)
 {
  return context.SetValue(kBaggageHeader, baggage);
 }
--- a/api/include/opentelemetry/baggage/propagation/baggage_propagator.h
+++ b/api/include/opentelemetry/baggage/propagation/baggage_propagator.h
@ -3,15 +3,9 @@

 #pragma once

-#include <memory>
-#include <string>
-
 #include "opentelemetry/baggage/baggage.h"
 #include "opentelemetry/baggage/baggage_context.h"
-#include "opentelemetry/context/context.h"
 #include "opentelemetry/context/propagation/text_map_propagator.h"
-#include "opentelemetry/nostd/function_ref.h"
-#include "opentelemetry/nostd/string_view.h"
 #include "opentelemetry/version.h"

 OPENTELEMETRY_BEGIN_NAMESPACE
@ -20,34 +14,22 @@ namespace baggage
 namespace propagation
 {

-class BaggagePropagator : public context::propagation::TextMapPropagator
+class BaggagePropagator : public opentelemetry::context::propagation::TextMapPropagator
 {
 public:
-  void Inject(context::propagation::TextMapCarrier &carrier,
-              const context::Context &context) noexcept override
+  void Inject(opentelemetry::context::propagation::TextMapCarrier &carrier,
+              const opentelemetry::context::Context &context) noexcept override
  {
-    auto baggage = baggage::GetBaggage(context);
-    auto header  = baggage->ToHeader();
-    if (header.size())
-    {
-      carrier.Set(kBaggageHeader, header);
-    }
+    auto baggage = opentelemetry::baggage::GetBaggage(context);
+    carrier.Set(kBaggageHeader, baggage->ToHeader());
  }

-  context::Context Extract(const context::propagation::TextMapCarrier &carrier,
-                           context::Context &context) noexcept override
+  context::Context Extract(const opentelemetry::context::propagation::TextMapCarrier &carrier,
+                           opentelemetry::context::Context &context) noexcept override
  {
-    nostd::string_view baggage_str = carrier.Get(baggage::kBaggageHeader);
-    auto baggage                   = baggage::Baggage::FromHeader(baggage_str);
-
-    if (baggage->ToHeader().size())
-    {
-      return baggage::SetBaggage(context, baggage);
-    }
-    else
-    {
-      return context;
-    }
+    nostd::string_view baggage_str = carrier.Get(opentelemetry::baggage::kBaggageHeader);
+    auto baggage                   = opentelemetry::baggage::Baggage::FromHeader(baggage_str);
+    return opentelemetry::baggage::SetBaggage(context, baggage);
  }

  bool Fields(nostd::function_ref<bool(nostd::string_view)> callback) const noexcept override
--- a/api/include/opentelemetry/common/attribute_value.h
+++ b/api/include/opentelemetry/common/attribute_value.h
@ -23,13 +23,12 @@ namespace common
 ///    (IEEE 754-1985) or signed 64 bit integer.
 ///  - Homogenous arrays of primitive type values.
 ///
-/// \warning The OpenTelemetry C++ API does not support the following attribute:
-///  uint64_t, nostd::span<const uint64_t>, and nostd::span<const uint8_t> types.
+/// \warning
 /// \parblock The OpenTelemetry C++ API currently supports several attribute
 /// value types that are not covered by the OpenTelemetry specification:
 ///  - \c uint64_t
 ///  - \c nostd::span<const uint64_t>
-///  - \c nostd::span<const uint8_t>
+///  - \c nostd::span<uint8_t>
 ///
 /// Those types are reserved for future use and currently should not be
 /// used. There are no guarantees around how those values are handled by
@ -55,6 +54,8 @@ using AttributeValue =
                   // Not currently supported by the specification, but reserved for future use.
                   // Added to provide support for all primitive C++ types.
                   nostd::span<const uint64_t>,
+                   // Not currently supported by the specification, but reserved for future use.
+                   // See https://github.com/open-telemetry/opentelemetry-specification/issues/780
                   nostd::span<const uint8_t>>;

 enum AttributeType
--- a/api/include/opentelemetry/common/key_value_iterable.h
+++ b/api/include/opentelemetry/common/key_value_iterable.h
@ -5,7 +5,6 @@

 #include "opentelemetry/common/attribute_value.h"
 #include "opentelemetry/nostd/function_ref.h"
-#include "opentelemetry/nostd/string_view.h"
 #include "opentelemetry/version.h"

 OPENTELEMETRY_BEGIN_NAMESPACE
@ -33,31 +32,5 @@ public:
   */
  virtual size_t size() const noexcept = 0;
 };
-
-/**
- * Supports internal iteration over a collection of key-value pairs.
- */
-class NoopKeyValueIterable : public KeyValueIterable
-{
-public:
-  ~NoopKeyValueIterable() override = default;
-
-  /**
-   * No-op implementation: does not invoke the callback, even if key-value pairs are present.
-   * @return true without iterating or invoking the callback
-   */
-  bool ForEachKeyValue(
-      nostd::function_ref<bool(nostd::string_view, common::AttributeValue)> /*callback*/)
-      const noexcept override
-  {
-    return true;
-  }
-
-  /**
-   * @return the number of key-value pairs
-   */
-  size_t size() const noexcept override { return 0; }
-};
-
 }  // namespace common
 OPENTELEMETRY_END_NAMESPACE
--- a/api/include/opentelemetry/common/key_value_iterable_view.h
+++ b/api/include/opentelemetry/common/key_value_iterable_view.h
@ -3,19 +3,11 @@

 #pragma once

-#include <stddef.h>
-#include <initializer_list>
 #include <iterator>
 #include <type_traits>
 #include <utility>
-#include <vector>

-#include "opentelemetry/common/attribute_value.h"
 #include "opentelemetry/common/key_value_iterable.h"
-#include "opentelemetry/nostd/function_ref.h"
-#include "opentelemetry/nostd/span.h"
-#include "opentelemetry/nostd/string_view.h"
-#include "opentelemetry/nostd/type_traits.h"
 #include "opentelemetry/nostd/utility.h"
 #include "opentelemetry/version.h"

@ -81,67 +73,5 @@ public:
 private:
  const T *container_;
 };
-
-template <class T, nostd::enable_if_t<detail::is_key_value_iterable<T>::value> * = nullptr>
-KeyValueIterableView<T> MakeKeyValueIterableView(const T &container) noexcept
-{
-  return KeyValueIterableView<T>(container);
-}
-
-/**
- * Utility function to help to make a attribute view from initializer_list
- *
- * @param attributes The initializer_list of key-value pairs
- * @return nostd::span<const std::pair<nostd::string_view, common::AttributeValue>>
- */
-inline static nostd::span<const std::pair<nostd::string_view, common::AttributeValue>>
-MakeAttributes(std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>>
-                   attributes) noexcept
-{
-  return nostd::span<const std::pair<nostd::string_view, common::AttributeValue>>{
-      attributes.begin(), attributes.end()};
-}
-
-/**
- * Utility function to help to make a attribute view from a span
- *
- * @param attributes The span of key-value pairs
- * @return nostd::span<const std::pair<nostd::string_view, common::AttributeValue>>
- */
-inline static nostd::span<const std::pair<nostd::string_view, common::AttributeValue>>
-MakeAttributes(
-    nostd::span<const std::pair<nostd::string_view, common::AttributeValue>> attributes) noexcept
-{
-  return attributes;
-}
-
-/**
- * Utility function to help to make a attribute view from a KeyValueIterable
- *
- * @param attributes The KeyValueIterable of key-value pairs
- * @return common::KeyValueIterable
- */
-inline static const common::KeyValueIterable &MakeAttributes(
-    const common::KeyValueIterable &attributes) noexcept
-{
-  return attributes;
-}
-
-/**
- * Utility function to help to make a attribute view from a key-value iterable object
- *
- * @tparam ArgumentType  Expected to be ArgumentType
- * @param attributes     The key-value iterable object
- * @return nostd::span<const std::pair<nostd::string_view, common::AttributeValue>>
- */
-template <
-    class ArgumentType,
-    nostd::enable_if_t<common::detail::is_key_value_iterable<ArgumentType>::value> * = nullptr>
-inline static common::KeyValueIterableView<ArgumentType> MakeAttributes(
-    const ArgumentType &attributes) noexcept
-{
-  return common::KeyValueIterableView<ArgumentType>(attributes);
-}
-
 }  // namespace common
 OPENTELEMETRY_END_NAMESPACE
--- a/api/include/opentelemetry/common/kv_properties.h
+++ b/api/include/opentelemetry/common/kv_properties.h
@ -6,6 +6,7 @@
 #include "opentelemetry/common/key_value_iterable_view.h"
 #include "opentelemetry/common/string_util.h"
 #include "opentelemetry/nostd/function_ref.h"
+#include "opentelemetry/nostd/shared_ptr.h"
 #include "opentelemetry/nostd/string_view.h"
 #include "opentelemetry/nostd/unique_ptr.h"
 #include "opentelemetry/version.h"
@ -32,7 +33,7 @@ class KeyValueStringTokenizer
 public:
  KeyValueStringTokenizer(
      nostd::string_view str,
-      const KeyValueStringTokenizerOptions &opts = KeyValueStringTokenizerOptions()) noexcept
+      const KeyValueStringTokenizerOptions &opts = KeyValueStringTokenizerOptions())
      : str_(str), opts_(opts), index_(0)
  {}

@ -47,7 +48,7 @@ public:
  // @param key : key in kv pair
  // @param key : value in kv pair
  // @returns true if next kv pair was found, false otherwise.
-  bool next(bool &valid_kv, nostd::string_view &key, nostd::string_view &value) noexcept
+  bool next(bool &valid_kv, nostd::string_view &key, nostd::string_view &value)
  {
    valid_kv = true;
    while (index_ < str_.size())
@ -158,7 +159,7 @@ public:
    }

    // Move contructor and assignment operator
-    Entry(Entry &&other)            = default;
+    Entry(Entry &&other) = default;
    Entry &operator=(Entry &&other) = default;

    // Creates an Entry for a given key-value pair.
@ -169,13 +170,13 @@ public:
    }

    // Gets the key associated with this entry.
-    nostd::string_view GetKey() const noexcept { return key_.get(); }
+    nostd::string_view GetKey() const { return key_.get(); }

    // Gets the value associated with this entry.
-    nostd::string_view GetValue() const noexcept { return value_.get(); }
+    nostd::string_view GetValue() const { return value_.get(); }

    // Sets the value for this entry. This overrides the previous value.
-    void SetValue(nostd::string_view value) noexcept { value_ = CopyStringToPointer(value); }
+    void SetValue(nostd::string_view value) { value_ = CopyStringToPointer(value); }

  private:
    // Store key and value as raw char pointers to avoid using std::string.
@ -205,15 +206,15 @@ public:
 public:
  // Create Key-value list of given size
  // @param size : Size of list.
-  KeyValueProperties(size_t size) noexcept
+  KeyValueProperties(size_t size)
      : num_entries_(0), max_num_entries_(size), entries_(new Entry[size])
  {}

  // Create Empty Key-Value list
-  KeyValueProperties() noexcept : num_entries_(0), max_num_entries_(0), entries_(nullptr) {}
+  KeyValueProperties() : num_entries_(0), max_num_entries_(0), entries_(nullptr) {}

  template <class T, class = typename std::enable_if<detail::is_key_value_iterable<T>::value>::type>
-  KeyValueProperties(const T &keys_and_values) noexcept
+  KeyValueProperties(const T &keys_and_values)
      : num_entries_(0),
        max_num_entries_(keys_and_values.size()),
        entries_(new Entry[max_num_entries_])
@ -226,7 +227,7 @@ public:
  }

  // Adds new kv pair into kv properties
-  void AddEntry(nostd::string_view key, nostd::string_view value) noexcept
+  void AddEntry(nostd::string_view key, nostd::string_view value)
  {
    if (num_entries_ < max_num_entries_)
    {
@ -237,7 +238,7 @@ public:

  // Returns all kv pair entries
  bool GetAllEntries(
-      nostd::function_ref<bool(nostd::string_view, nostd::string_view)> callback) const noexcept
+      nostd::function_ref<bool(nostd::string_view, nostd::string_view)> callback) const
  {
    for (size_t i = 0; i < num_entries_; i++)
    {
@ -251,7 +252,7 @@ public:
  }

  // Return value for key if exists, return false otherwise
-  bool GetValue(nostd::string_view key, std::string &value) const noexcept
+  bool GetValue(nostd::string_view key, std::string &value) const
  {
    for (size_t i = 0; i < num_entries_; i++)
    {
@ -269,4 +270,4 @@ public:
  size_t Size() const noexcept { return num_entries_; }
 };
 }  // namespace common
-OPENTELEMETRY_END_NAMESPACE
+OPENTELEMETRY_END_NAMESPACE
--- a/api/include/opentelemetry/common/macros.h
+++ b/api/include/opentelemetry/common/macros.h
@ -1,523 +0,0 @@
-// Copyright The OpenTelemetry Authors
-// SPDX-License-Identifier: Apache-2.0
-
-#pragma once
-
-/*
-   OPENTELEMETRY_HAVE_BUILTIN&OPENTELEMETRY_HAVE_FEATURE
-
-   Checks whether the compiler supports a Clang Feature Checking Macro, and if
-   so, checks whether it supports the provided builtin function "x" where x
-   is one of the functions noted in
-   https://clang.llvm.org/docs/LanguageExtensions.html
-
-   Note: Use this macro to avoid an extra level of #ifdef __has_builtin check.
-   http://releases.llvm.org/3.3/tools/clang/docs/LanguageExtensions.html
-*/
-#if !defined(OPENTELEMETRY_HAVE_BUILTIN)
-#  ifdef __has_builtin
-#    define OPENTELEMETRY_HAVE_BUILTIN(x) __has_builtin(x)
-#  else
-#    define OPENTELEMETRY_HAVE_BUILTIN(x) 0
-#  endif
-#endif
-
-#if !defined(OPENTELEMETRY_HAVE_FEATURE)
-#  ifdef __has_feature
-#    define OPENTELEMETRY_HAVE_FEATURE(f) __has_feature(f)
-#  else
-#    define OPENTELEMETRY_HAVE_FEATURE(f) 0
-#  endif
-#endif
-
-/*
-   has feature
-
-   OPENTELEMETRY_HAVE_ATTRIBUTE
-
-   A function-like feature checking macro that is a wrapper around
-   `__has_attribute`, which is defined by GCC 5+ and Clang and evaluates to a
-   nonzero constant integer if the attribute is supported or 0 if not.
-
-   It evaluates to zero if `__has_attribute` is not defined by the compiler.
-
-   GCC: https://gcc.gnu.org/gcc-5/changes.html
-   Clang: https://clang.llvm.org/docs/LanguageExtensions.html
-*/
-#if !defined(OPENTELEMETRY_HAVE_ATTRIBUTE)
-#  ifdef __has_attribute
-#    define OPENTELEMETRY_HAVE_ATTRIBUTE(x) __has_attribute(x)
-#  else
-#    define OPENTELEMETRY_HAVE_ATTRIBUTE(x) 0
-#  endif
-#endif
-
-/*
-   OPENTELEMETRY_HAVE_CPP_ATTRIBUTE
-
-   A function-like feature checking macro that accepts C++11 style attributes.
-   It's a wrapper around `__has_cpp_attribute`, defined by ISO C++ SD-6
-   (https://en.cppreference.com/w/cpp/experimental/feature_test). If we don't
-   find `__has_cpp_attribute`, will evaluate to 0.
-*/
-#if !defined(OPENTELEMETRY_HAVE_CPP_ATTRIBUTE)
-#  if defined(__cplusplus) && defined(__has_cpp_attribute)
-// NOTE: requiring __cplusplus above should not be necessary, but
-// works around https://bugs.llvm.org/show_bug.cgi?id=23435.
-#    define OPENTELEMETRY_HAVE_CPP_ATTRIBUTE(x) __has_cpp_attribute(x)
-#  else
-#    define OPENTELEMETRY_HAVE_CPP_ATTRIBUTE(x) 0
-#  endif
-#endif
-
-/*
-   Expected usage pattern:
-
-   if OPENTELEMETRY_LIKELY_CONDITION (ptr != nullptr)
-   {
-     do_something_likely();
-   } else {
-     do_something_unlikely();
-   }
-
-   This pattern works with gcc/clang and __builtin_expect(),
-   as well as with C++20.
-   It is unclear if __builtin_expect() will be deprecated
-   in favor of C++20 [[likely]] or not.
-
-   OPENTELEMETRY_LIKELY_CONDITION is preferred over OPENTELEMETRY_LIKELY,
-   to be revisited when C++20 is required.
-*/
-
-#if !defined(OPENTELEMETRY_LIKELY_CONDITION) && defined(__cplusplus)
-// Only use likely with C++20
-#  if __cplusplus >= 202002L
-// GCC 9 has likely attribute but do not support declare it at the beginning of statement
-#    if defined(__has_cpp_attribute) && (defined(__clang__) || !defined(__GNUC__) || __GNUC__ > 9)
-#      if __has_cpp_attribute(likely)
-#        define OPENTELEMETRY_LIKELY_CONDITION(C) (C) [[likely]]
-#      endif
-#    endif
-#  endif
-#endif
-#if !defined(OPENTELEMETRY_LIKELY_CONDITION) && (defined(__clang__) || defined(__GNUC__))
-// Only use if supported by the compiler
-#  define OPENTELEMETRY_LIKELY_CONDITION(C) (__builtin_expect(!!(C), true))
-#endif
-#ifndef OPENTELEMETRY_LIKELY_CONDITION
-// Do not use likely annotations
-#  define OPENTELEMETRY_LIKELY_CONDITION(C) (C)
-#endif
-
-#if !defined(OPENTELEMETRY_UNLIKELY_CONDITION) && defined(__cplusplus)
-// Only use unlikely with C++20
-#  if __cplusplus >= 202002L
-// GCC 9 has unlikely attribute but do not support declare it at the beginning of statement
-#    if defined(__has_cpp_attribute) && (defined(__clang__) || !defined(__GNUC__) || __GNUC__ > 9)
-#      if __has_cpp_attribute(unlikely)
-#        define OPENTELEMETRY_UNLIKELY_CONDITION(C) (C) [[unlikely]]
-#      endif
-#    endif
-#  endif
-#endif
-#if !defined(OPENTELEMETRY_UNLIKELY_CONDITION) && (defined(__clang__) || defined(__GNUC__))
-// Only use if supported by the compiler
-#  define OPENTELEMETRY_UNLIKELY_CONDITION(C) (__builtin_expect(!!(C), false))
-#endif
-#ifndef OPENTELEMETRY_UNLIKELY_CONDITION
-// Do not use unlikely annotations
-#  define OPENTELEMETRY_UNLIKELY_CONDITION(C) (C)
-#endif
-
-/*
-   Expected usage pattern:
-
-   if (ptr != nullptr)
-   OPENTELEMETRY_LIKELY
-   {
-     do_something_likely();
-   } else {
-     do_something_unlikely();
-   }
-
-   This pattern works starting with C++20.
-   See https://en.cppreference.com/w/cpp/language/attributes/likely
-
-   Please use OPENTELEMETRY_LIKELY_CONDITION instead for now.
-*/
-
-#if !defined(OPENTELEMETRY_LIKELY) && defined(__cplusplus)
-// Only use likely with C++20
-#  if __cplusplus >= 202002L
-// GCC 9 has likely attribute but do not support declare it at the beginning of statement
-#    if defined(__has_cpp_attribute) && (defined(__clang__) || !defined(__GNUC__) || __GNUC__ > 9)
-#      if __has_cpp_attribute(likely)
-#        define OPENTELEMETRY_LIKELY [[likely]]
-#      endif
-#    endif
-#  endif
-#endif
-
-#ifndef OPENTELEMETRY_LIKELY
-#  define OPENTELEMETRY_LIKELY
-#endif
-
-#if !defined(OPENTELEMETRY_UNLIKELY) && defined(__cplusplus)
-// Only use unlikely with C++20
-#  if __cplusplus >= 202002L
-// GCC 9 has unlikely attribute but do not support declare it at the beginning of statement
-#    if defined(__has_cpp_attribute) && (defined(__clang__) || !defined(__GNUC__) || __GNUC__ > 9)
-#      if __has_cpp_attribute(unlikely)
-#        define OPENTELEMETRY_UNLIKELY [[unlikely]]
-#      endif
-#    endif
-#  endif
-#endif
-
-#ifndef OPENTELEMETRY_UNLIKELY
-#  define OPENTELEMETRY_UNLIKELY
-#endif
-
-/// \brief Declare variable as maybe unused
-/// usage:
-///   OPENTELEMETRY_MAYBE_UNUSED int a;
-///   class OPENTELEMETRY_MAYBE_UNUSED a;
-///   OPENTELEMETRY_MAYBE_UNUSED int a();
-///
-#if defined(__cplusplus) && __cplusplus >= 201703L
-#  define OPENTELEMETRY_MAYBE_UNUSED [[maybe_unused]]
-#elif defined(__clang__)
-#  define OPENTELEMETRY_MAYBE_UNUSED __attribute__((unused))
-#elif defined(__GNUC__) && ((__GNUC__ >= 4) || ((__GNUC__ == 3) && (__GNUC_MINOR__ >= 1)))
-#  define OPENTELEMETRY_MAYBE_UNUSED __attribute__((unused))
-#elif (defined(_MSC_VER) && _MSC_VER >= 1910) && (defined(_MSVC_LANG) && _MSVC_LANG >= 201703L)
-#  define OPENTELEMETRY_MAYBE_UNUSED [[maybe_unused]]
-#else
-#  define OPENTELEMETRY_MAYBE_UNUSED
-#endif
-
-#ifndef OPENTELEMETRY_RTTI_ENABLED
-#  if defined(__clang__)
-#    if __has_feature(cxx_rtti)
-#      define OPENTELEMETRY_RTTI_ENABLED
-#    endif
-#  elif defined(__GNUG__)
-#    if defined(__GXX_RTTI)
-#      define OPENTELEMETRY_RTTI_ENABLED
-#    endif
-#  elif defined(_MSC_VER)
-#    if defined(_CPPRTTI)
-#      define OPENTELEMETRY_RTTI_ENABLED
-#    endif
-#  endif
-#endif
-
-#if defined(__cplusplus) && __cplusplus >= 201402L
-#  define OPENTELEMETRY_DEPRECATED [[deprecated]]
-#elif defined(__clang__)
-#  define OPENTELEMETRY_DEPRECATED __attribute__((deprecated))
-#elif defined(__GNUC__)
-#  define OPENTELEMETRY_DEPRECATED __attribute__((deprecated))
-#elif defined(_MSC_VER)
-#  if _MSC_VER >= 1910 && defined(_MSVC_LANG) && _MSVC_LANG >= 201703L
-#    define OPENTELEMETRY_DEPRECATED [[deprecated]]
-#  else
-#    define OPENTELEMETRY_DEPRECATED __declspec(deprecated)
-#  endif
-#else
-#  define OPENTELEMETRY_DEPRECATED
-#endif
-
-#if defined(__cplusplus) && __cplusplus >= 201402L
-#  define OPENTELEMETRY_DEPRECATED_MESSAGE(msg) [[deprecated(msg)]]
-#elif defined(__clang__)
-#  define OPENTELEMETRY_DEPRECATED_MESSAGE(msg) __attribute__((deprecated(msg)))
-#elif defined(__GNUC__)
-#  define OPENTELEMETRY_DEPRECATED_MESSAGE(msg) __attribute__((deprecated(msg)))
-#elif defined(_MSC_VER)
-#  if _MSC_VER >= 1910 && defined(_MSVC_LANG) && _MSVC_LANG >= 201703L
-#    define OPENTELEMETRY_DEPRECATED_MESSAGE(msg) [[deprecated(msg)]]
-#  else
-#    define OPENTELEMETRY_DEPRECATED_MESSAGE(msg) __declspec(deprecated(msg))
-#  endif
-#else
-#  define OPENTELEMETRY_DEPRECATED_MESSAGE(msg)
-#endif
-
-// Regex support
-#if (__GNUC__ == 4 && (__GNUC_MINOR__ == 8 || __GNUC_MINOR__ == 9))
-#  define OPENTELEMETRY_HAVE_WORKING_REGEX 0
-#else
-#  define OPENTELEMETRY_HAVE_WORKING_REGEX 1
-#endif
-
-/* clang-format off */
-
-/**
-  @page HEADER_ONLY_SINGLETON Header only singleton.
-
-  @section ELF_SINGLETON
-
-  For clang and gcc, the desired coding pattern is as follows.
-
-  @verbatim
-  class Foo
-  {
-    // (a)
-    __attribute__((visibility("default")))
-    // (b)
-    T& get_singleton()
-    {
-      // (c)
-      static T singleton;
-      return singleton;
-    }
-  };
-  @endverbatim
-
-  (a) is needed when the code is build with
-  @code -fvisibility="hidden" @endcode
-  to ensure that all instances of (b) are visible to the linker.
-
-  What is duplicated in the binary is @em code, in (b).
-
-  The linker will make sure only one instance
-  of all the (b) methods is used.
-
-  (c) is a singleton implemented inside a method.
-
-  This is very desirable, because:
-
-  - the C++ compiler guarantees that construction
-    of the variable (c) is thread safe.
-
-  - constructors for (c) singletons are executed in code path order,
-    or not at all if the singleton is never used.
-
-  @section OTHER_SINGLETON
-
-  For other platforms, header only singletons are not supported at this
-point.
-
-  @section CODING_PATTERN
-
-  The coding pattern to use in the source code is as follows
-
-  @verbatim
-  class Foo
-  {
-    OPENTELEMETRY_API_SINGLETON
-    T& get_singleton()
-    {
-      static T singleton;
-      return singleton;
-    }
-  };
-  @endverbatim
-*/
-
-/* clang-format on */
-
-#if defined(__clang__)
-
-#  define OPENTELEMETRY_API_SINGLETON __attribute__((visibility("default")))
-#  define OPENTELEMETRY_LOCAL_SYMBOL __attribute__((visibility("hidden")))
-
-#elif defined(__GNUC__)
-
-#  define OPENTELEMETRY_API_SINGLETON __attribute__((visibility("default")))
-#  define OPENTELEMETRY_LOCAL_SYMBOL __attribute__((visibility("hidden")))
-
-#else
-
-/* Add support for other compilers here. */
-
-#  define OPENTELEMETRY_API_SINGLETON
-#  define OPENTELEMETRY_LOCAL_SYMBOL
-
-#endif
-
-//
-// Atomic wrappers based on compiler intrinsics for memory read/write.
-// The tailing number is read/write length in bits.
-//
-// N.B. Compiler intrinsic is used because the usage of C++ standard library is restricted in the
-// OpenTelemetry C++ API.
-//
-#if defined(__GNUC__)
-
-#  define OPENTELEMETRY_ATOMIC_READ_8(ptr) __atomic_load_n(ptr, __ATOMIC_SEQ_CST)
-#  define OPENTELEMETRY_ATOMIC_WRITE_8(ptr, value) __atomic_store_n(ptr, value, __ATOMIC_SEQ_CST)
-
-#elif defined(_MSC_VER)
-
-#  include <intrin.h>
-
-#  define OPENTELEMETRY_ATOMIC_READ_8(ptr) \
-    static_cast<uint8_t>(_InterlockedCompareExchange8(reinterpret_cast<char *>(ptr), 0, 0))
-#  define OPENTELEMETRY_ATOMIC_WRITE_8(ptr, value) \
-    _InterlockedExchange8(reinterpret_cast<char *>(ptr), static_cast<char>(value))
-
-#else
-#  error port atomics read/write for the current platform
-#endif
-
-/* clang-format on */
-//
-// The if/elif order matters here. If both OPENTELEMETRY_BUILD_IMPORT_DLL and
-// OPENTELEMETRY_BUILD_EXPORT_DLL are defined, the former takes precedence.
-//
-// TODO: consider define OPENTELEMETRY_EXPORT for cygwin/gcc, see below link.
-// https://gcc.gnu.org/wiki/Visibility#How_to_use_the_new_C.2B-.2B-_visibility_support
-//
-#if defined(_MSC_VER) && defined(OPENTELEMETRY_BUILD_IMPORT_DLL)
-
-#  define OPENTELEMETRY_EXPORT __declspec(dllimport)
-
-#elif defined(_MSC_VER) && defined(OPENTELEMETRY_BUILD_EXPORT_DLL)
-
-#  define OPENTELEMETRY_EXPORT __declspec(dllexport)
-
-#else
-
-//
-// build OpenTelemetry as static library or not on Windows.
-//
-#  define OPENTELEMETRY_EXPORT
-
-#endif
-
-// OPENTELEMETRY_HAVE_EXCEPTIONS
-//
-// Checks whether the compiler both supports and enables exceptions. Many
-// compilers support a "no exceptions" mode that disables exceptions.
-//
-// Generally, when OPENTELEMETRY_HAVE_EXCEPTIONS is not defined:
-//
-// * Code using `throw` and `try` may not compile.
-// * The `noexcept` specifier will still compile and behave as normal.
-// * The `noexcept` operator may still return `false`.
-//
-// For further details, consult the compiler's documentation.
-#ifndef OPENTELEMETRY_HAVE_EXCEPTIONS
-#  if defined(__clang__) && ((__clang_major__ * 100) + __clang_minor__) < 306
-// Clang < 3.6
-// http://releases.llvm.org/3.6.0/tools/clang/docs/ReleaseNotes.html#the-exceptions-macro
-#    if defined(__EXCEPTIONS) && OPENTELEMETRY_HAVE_FEATURE(cxx_exceptions)
-#      define OPENTELEMETRY_HAVE_EXCEPTIONS 1
-#    endif  // defined(__EXCEPTIONS) && OPENTELEMETRY_HAVE_FEATURE(cxx_exceptions)
-#  elif OPENTELEMETRY_HAVE_FEATURE(cxx_exceptions)
-#    define OPENTELEMETRY_HAVE_EXCEPTIONS 1
-// Handle remaining special cases and default to exceptions being supported.
-#  elif !(defined(__GNUC__) && !defined(__EXCEPTIONS) && !defined(__cpp_exceptions)) && \
-      !(defined(_MSC_VER) && !defined(_CPPUNWIND))
-#    define OPENTELEMETRY_HAVE_EXCEPTIONS 1
-#  endif
-#endif
-#ifndef OPENTELEMETRY_HAVE_EXCEPTIONS
-#  define OPENTELEMETRY_HAVE_EXCEPTIONS 0
-#endif
-
-/*
-   OPENTELEMETRY_ATTRIBUTE_LIFETIME_BOUND indicates that a resource owned by a function
-   parameter or implicit object parameter is retained by the return value of the
-   annotated function (or, for a parameter of a constructor, in the value of the
-   constructed object). This attribute causes warnings to be produced if a
-   temporary object does not live long enough.
-
-   When applied to a reference parameter, the referenced object is assumed to be
-   retained by the return value of the function. When applied to a non-reference
-   parameter (for example, a pointer or a class type), all temporaries
-   referenced by the parameter are assumed to be retained by the return value of
-   the function.
-
-   See also the upstream documentation:
-   https://clang.llvm.org/docs/AttributeReference.html#lifetimebound
-*/
-#ifndef OPENTELEMETRY_ATTRIBUTE_LIFETIME_BOUND
-#  if OPENTELEMETRY_HAVE_CPP_ATTRIBUTE(clang::lifetimebound)
-#    define OPENTELEMETRY_ATTRIBUTE_LIFETIME_BOUND [[clang::lifetimebound]]
-#  elif OPENTELEMETRY_HAVE_ATTRIBUTE(lifetimebound)
-#    define OPENTELEMETRY_ATTRIBUTE_LIFETIME_BOUND __attribute__((lifetimebound))
-#  else
-#    define OPENTELEMETRY_ATTRIBUTE_LIFETIME_BOUND
-#  endif
-#endif
-
-// OPENTELEMETRY_HAVE_MEMORY_SANITIZER
-//
-// MemorySanitizer (MSan) is a detector of uninitialized reads. It consists of
-// a compiler instrumentation module and a run-time library.
-#ifndef OPENTELEMETRY_HAVE_MEMORY_SANITIZER
-#  if !defined(__native_client__) && OPENTELEMETRY_HAVE_FEATURE(memory_sanitizer)
-#    define OPENTELEMETRY_HAVE_MEMORY_SANITIZER 1
-#  else
-#    define OPENTELEMETRY_HAVE_MEMORY_SANITIZER 0
-#  endif
-#endif
-
-#if OPENTELEMETRY_HAVE_MEMORY_SANITIZER && OPENTELEMETRY_HAVE_ATTRIBUTE(no_sanitize_memory)
-#  define OPENTELEMETRY_SANITIZER_NO_MEMORY \
-    __attribute__((no_sanitize_memory))  // __attribute__((no_sanitize("memory")))
-#else
-#  define OPENTELEMETRY_SANITIZER_NO_MEMORY
-#endif
-
-// OPENTELEMETRY_HAVE_THREAD_SANITIZER
-//
-// ThreadSanitizer (TSan) is a fast data race detector.
-#ifndef OPENTELEMETRY_HAVE_THREAD_SANITIZER
-#  if defined(__SANITIZE_THREAD__)
-#    define OPENTELEMETRY_HAVE_THREAD_SANITIZER 1
-#  elif OPENTELEMETRY_HAVE_FEATURE(thread_sanitizer)
-#    define OPENTELEMETRY_HAVE_THREAD_SANITIZER 1
-#  else
-#    define OPENTELEMETRY_HAVE_THREAD_SANITIZER 0
-#  endif
-#endif
-
-#if OPENTELEMETRY_HAVE_THREAD_SANITIZER && OPENTELEMETRY_HAVE_ATTRIBUTE(no_sanitize_thread)
-#  define OPENTELEMETRY_SANITIZER_NO_THREAD \
-    __attribute__((no_sanitize_thread))  // __attribute__((no_sanitize("thread")))
-#else
-#  define OPENTELEMETRY_SANITIZER_NO_THREAD
-#endif
-
-// OPENTELEMETRY_HAVE_ADDRESS_SANITIZER
-//
-// AddressSanitizer (ASan) is a fast memory error detector.
-#ifndef OPENTELEMETRY_HAVE_ADDRESS_SANITIZER
-#  if defined(__SANITIZE_ADDRESS__)
-#    define OPENTELEMETRY_HAVE_ADDRESS_SANITIZER 1
-#  elif OPENTELEMETRY_HAVE_FEATURE(address_sanitizer)
-#    define OPENTELEMETRY_HAVE_ADDRESS_SANITIZER 1
-#  else
-#    define OPENTELEMETRY_HAVE_ADDRESS_SANITIZER 0
-#  endif
-#endif
-
-// OPENTELEMETRY_HAVE_HWADDRESS_SANITIZER
-//
-// Hardware-Assisted AddressSanitizer (or HWASAN) is even faster than asan
-// memory error detector which can use CPU features like ARM TBI, Intel LAM or
-// AMD UAI.
-#ifndef OPENTELEMETRY_HAVE_HWADDRESS_SANITIZER
-#  if defined(__SANITIZE_HWADDRESS__)
-#    define OPENTELEMETRY_HAVE_HWADDRESS_SANITIZER 1
-#  elif OPENTELEMETRY_HAVE_FEATURE(hwaddress_sanitizer)
-#    define OPENTELEMETRY_HAVE_HWADDRESS_SANITIZER 1
-#  else
-#    define OPENTELEMETRY_HAVE_HWADDRESS_SANITIZER 0
-#  endif
-#endif
-
-#if OPENTELEMETRY_HAVE_ADDRESS_SANITIZER && OPENTELEMETRY_HAVE_ATTRIBUTE(no_sanitize_address)
-#  define OPENTELEMETRY_SANITIZER_NO_ADDRESS \
-    __attribute__((no_sanitize_address))  // __attribute__((no_sanitize("address")))
-#elif OPENTELEMETRY_HAVE_ADDRESS_SANITIZER && defined(_MSC_VER) && _MSC_VER >= 1928
-#  define OPENTELEMETRY_SANITIZER_NO_ADDRESS __declspec(no_sanitize_address)
-#elif OPENTELEMETRY_HAVE_HWADDRESS_SANITIZER && OPENTELEMETRY_HAVE_ATTRIBUTE(no_sanitize)
-#  define OPENTELEMETRY_SANITIZER_NO_ADDRESS __attribute__((no_sanitize("hwaddress")))
-#else
-#  define OPENTELEMETRY_SANITIZER_NO_ADDRESS
-#endif
--- a/api/include/opentelemetry/common/spin_lock_mutex.h
+++ b/api/include/opentelemetry/common/spin_lock_mutex.h
@ -10,13 +10,13 @@
 #include "opentelemetry/version.h"

 #if defined(_MSC_VER)
-#  define _WINSOCKAPI_  // stops including winsock.h
+#  ifndef NOMINMAX
+#    define NOMINMAX
+#  endif
 #  include <windows.h>
 #elif defined(__i386__) || defined(__x86_64__)
 #  if defined(__clang__)
 #    include <emmintrin.h>
-#  elif defined(__INTEL_COMPILER)
-#    include <immintrin.h>
 #  endif
 #endif

@ -53,29 +53,10 @@ class SpinLockMutex
 {
 public:
  SpinLockMutex() noexcept {}
-  ~SpinLockMutex() noexcept                       = default;
-  SpinLockMutex(const SpinLockMutex &)            = delete;
+  ~SpinLockMutex() noexcept            = default;
+  SpinLockMutex(const SpinLockMutex &) = delete;
  SpinLockMutex &operator=(const SpinLockMutex &) = delete;
-
-  static inline void fast_yield() noexcept
-  {
-// Issue a Pause/Yield instruction while spinning.
-#if defined(_MSC_VER)
-    YieldProcessor();
-#elif defined(__i386__) || defined(__x86_64__)
-#  if defined(__clang__) || defined(__INTEL_COMPILER)
-    _mm_pause();
-#  else
-    __builtin_ia32_pause();
-#  endif
-#elif defined(__armel__) || defined(__ARMEL__)
-    asm volatile("nop" ::: "memory");
-#elif defined(__arm__) || defined(__aarch64__)  // arm big endian / arm64
-    __asm__ __volatile__("yield" ::: "memory");
-#else
-    // TODO: Issue PAGE/YIELD on other architectures.
-#endif
-  }
+  SpinLockMutex &operator=(const SpinLockMutex &) volatile = delete;

  /**
   * Attempts to lock the mutex.  Return immediately with `true` (success) or `false` (failure).
@ -109,7 +90,22 @@ public:
        {
          return;
        }
-        fast_yield();
+// Issue a Pause/Yield instruction while spinning.
+#if defined(_MSC_VER)
+        YieldProcessor();
+#elif defined(__i386__) || defined(__x86_64__)
+#  if defined(__clang__)
+        _mm_pause();
+#  else
+        __builtin_ia32_pause();
+#  endif
+#elif defined(__arm__)
+        // This intrinsic should fail to be found if YIELD is not supported on the current
+        // processor.
+        __yield();
+#else
+        // TODO: Issue PAGE/YIELD on other architectures.
+#endif
      }
      // Yield then try again (goal ~100ns)
      std::this_thread::yield();
--- a/api/include/opentelemetry/common/string_util.h
+++ b/api/include/opentelemetry/common/string_util.h
@ -4,7 +4,20 @@
 #pragma once

 #include "opentelemetry/nostd/string_view.h"
-#include "opentelemetry/version.h"
+
+/** DJB2 hash function below is near-perfect hash used by several systems.
+ * Ref. http://www.cse.yorku.ca/~oz/hash.html
+ * </summary>
+ * <param name="str">String to hash</param>
+ * <param name="h">Initial offset</param>
+ * <returns>32 bit code</returns>
+ */
+constexpr uint32_t hashCode(const char *str, uint32_t h = 0)
+{
+  return (uint32_t)(!str[h] ? 5381 : ((uint32_t)hashCode(str, h + 1) * (uint32_t)33) ^ str[h]);
+}
+#define OTEL_CPP_CONST_UINT32_T(x) std::integral_constant<uint32_t, (uint32_t)x>::value
+#define OTEL_CPP_CONST_HASHCODE(name) OTEL_CPP_CONST_UINT32_T(hashCode(#name))

 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace common
@ -13,20 +26,20 @@ namespace common
 class StringUtil
 {
 public:
-  static nostd::string_view Trim(nostd::string_view str, size_t left, size_t right) noexcept
+  static nostd::string_view Trim(nostd::string_view str, size_t left, size_t right)
  {
-    while (left <= right && isspace(str[left]))
+    while (str[static_cast<std::size_t>(left)] == ' ' && left <= right)
    {
      left++;
    }
-    while (left <= right && isspace(str[right]))
+    while (str[static_cast<std::size_t>(right)] == ' ' && left <= right)
    {
      right--;
    }
    return str.substr(left, 1 + right - left);
  }

-  static nostd::string_view Trim(nostd::string_view str) noexcept
+  static nostd::string_view Trim(nostd::string_view str)
  {
    if (str.empty())
    {
--- a/api/include/opentelemetry/common/timestamp.h
+++ b/api/include/opentelemetry/common/timestamp.h
@ -3,6 +3,7 @@

 #pragma once

+#include <algorithm>
 #include <chrono>
 #include <cstdint>

@ -168,39 +169,5 @@ public:
 private:
  int64_t nanos_since_epoch_;
 };
-
-class DurationUtil
-{
-public:
-  template <class Rep, class Period>
-  static std::chrono::duration<Rep, Period> AdjustWaitForTimeout(
-      std::chrono::duration<Rep, Period> timeout,
-      std::chrono::duration<Rep, Period> indefinite_value) noexcept
-  {
-    // Do not call now() when this duration is max value, now() may have a expensive cost.
-    if (timeout == (std::chrono::duration<Rep, Period>::max)())
-    {
-      return indefinite_value;
-    }
-
-    // std::future<T>::wait_for, std::this_thread::sleep_for, and std::condition_variable::wait_for
-    // may use steady_clock or system_clock.We need make sure now() + timeout do not overflow.
-    auto max_timeout = std::chrono::duration_cast<std::chrono::duration<Rep, Period>>(
-        (std::chrono::steady_clock::time_point::max)() - std::chrono::steady_clock::now());
-    if (timeout >= max_timeout)
-    {
-      return indefinite_value;
-    }
-    max_timeout = std::chrono::duration_cast<std::chrono::duration<Rep, Period>>(
-        (std::chrono::system_clock::time_point::max)() - std::chrono::system_clock::now());
-    if (timeout >= max_timeout)
-    {
-      return indefinite_value;
-    }
-
-    return timeout;
-  }
-};
-
 }  // namespace common
 OPENTELEMETRY_END_NAMESPACE
--- a/api/include/opentelemetry/config.h
+++ b/api/include/opentelemetry/config.h
@ -3,17 +3,12 @@

 #pragma once

-#include <type_traits>  // IWYU pragma: keep
-
-#if defined(OPENTELEMETRY_ABI_VERSION_NO) && OPENTELEMETRY_ABI_VERSION_NO >= 2
-#  error \
-      "opentelemetry/config.h is removed in ABI version 2 and later. Please use opentelemetry/version.h instead."
+#ifndef __has_include
+#  define OPENTELEMETRY_HAS_INCLUDE(x) 0
 #else
-#  if defined(__clang__) || defined(__GNUC__)
-#    pragma GCC warning \
-        "opentelemetry/config.h is deprecated. Please use opentelemetry/version.h instead."
-#  elif defined(_MSC_VER)
-#    pragma message( \
-        "[WARNING]: opentelemetry/config.h is deprecated. Please use opentelemetry/version.h instead.")
-#  endif
+#  define OPENTELEMETRY_HAS_INCLUDE(x) __has_include(x)
+#endif
+
+#if !defined(__GLIBCXX__) || OPENTELEMETRY_HAS_INCLUDE(<codecvt>)  // >= libstdc++-5
+#  define OPENTELEMETRY_TRIVIALITY_TYPE_TRAITS
 #endif
--- a/api/include/opentelemetry/context/context.h
+++ b/api/include/opentelemetry/context/context.h
@ -1,16 +1,12 @@
-// Copyright The OpenTelemetry Authors
+// Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0

 #pragma once

 #include <cstring>
-#include <utility>
-
 #include "opentelemetry/context/context_value.h"
 #include "opentelemetry/nostd/shared_ptr.h"
 #include "opentelemetry/nostd/string_view.h"
-#include "opentelemetry/nostd/variant.h"
-#include "opentelemetry/version.h"

 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace context
@ -28,15 +24,17 @@ public:
  // Creates a context object from a map of keys and identifiers, this will
  // hold a shared_ptr to the head of the DataList linked list
  template <class T>
-  Context(const T &keys_and_values) noexcept
-      : head_{nostd::shared_ptr<DataList>{new DataList(keys_and_values)}}
-  {}
+  Context(const T &keys_and_values)
+  {
+    head_ = nostd::shared_ptr<DataList>{new DataList(keys_and_values)};
+  }

  // Creates a context object from a key and value, this will
  // hold a shared_ptr to the head of the DataList linked list
-  Context(nostd::string_view key, ContextValue value) noexcept
-      : head_{nostd::shared_ptr<DataList>{new DataList(key, value)}}
-  {}
+  Context(nostd::string_view key, ContextValue value)
+  {
+    head_ = nostd::shared_ptr<DataList>{new DataList(key, value)};
+  }

  // Accepts a new iterable and then returns a new context that
  // contains the new key and value data. It attaches the
@ -90,21 +88,22 @@ public:

 private:
  // A linked list to contain the keys and values of this context node
-  struct DataList
+  class DataList
  {
-    char *key_ = nullptr;
+  public:
+    char *key_;

-    nostd::shared_ptr<DataList> next_{nullptr};
+    nostd::shared_ptr<DataList> next_;

-    size_t key_length_ = 0UL;
+    size_t key_length_;

    ContextValue value_;

-    DataList() = default;
+    DataList() { next_ = nullptr; }

    // Builds a data list off of a key and value iterable and returns the head
    template <class T>
-    DataList(const T &keys_and_vals)
+    DataList(const T &keys_and_vals) : key_{nullptr}, next_(nostd::shared_ptr<DataList>{nullptr})
    {
      bool first = true;
      auto *node = this;
@ -129,18 +128,9 @@ private:
    {
      key_        = new char[key.size()];
      key_length_ = key.size();
-      std::memcpy(key_, key.data(), key.size() * sizeof(char));
-      next_  = nostd::shared_ptr<DataList>{nullptr};
+      memcpy(key_, key.data(), key.size() * sizeof(char));
      value_ = value;
-    }
-
-    DataList(const DataList &other)
-        : key_(new char[other.key_length_]),
-          next_(other.next_),
-          key_length_(other.key_length_),
-          value_(other.value_)
-    {
-      std::memcpy(key_, other.key_, other.key_length_ * sizeof(char));
+      next_  = nostd::shared_ptr<DataList>{nullptr};
    }

    DataList &operator=(DataList &&other) noexcept
--- a/api/include/opentelemetry/context/context_value.h
+++ b/api/include/opentelemetry/context/context_value.h
@ -5,22 +5,16 @@

 #include <cstdint>

+#include "opentelemetry/baggage/baggage.h"
 #include "opentelemetry/nostd/shared_ptr.h"
+#include "opentelemetry/nostd/span.h"
+#include "opentelemetry/nostd/unique_ptr.h"
 #include "opentelemetry/nostd/variant.h"
+#include "opentelemetry/trace/span.h"
+#include "opentelemetry/trace/span_context.h"
 #include "opentelemetry/version.h"

 OPENTELEMETRY_BEGIN_NAMESPACE
-namespace baggage
-{
-class Baggage;
-}  // namespace baggage
-
-namespace trace
-{
-class Span;
-class SpanContext;
-}  // namespace trace
-
 namespace context
 {
 using ContextValue = nostd::variant<nostd::monostate,
--- a/api/include/opentelemetry/context/propagation/composite_propagator.h
+++ b/api/include/opentelemetry/context/propagation/composite_propagator.h
@ -1,13 +1,10 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0

-#pragma once
-
+#include <initializer_list>
 #include <memory>
 #include <vector>
-
 #include "opentelemetry/context/propagation/text_map_propagator.h"
-#include "opentelemetry/version.h"

 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace context
@ -90,4 +87,4 @@ private:
 };
 }  // namespace propagation
 }  // namespace context
-OPENTELEMETRY_END_NAMESPACE
+OPENTELEMETRY_END_NAMESPACE;
--- a/api/include/opentelemetry/context/propagation/global_propagator.h
+++ b/api/include/opentelemetry/context/propagation/global_propagator.h
@ -6,8 +6,8 @@
 #include <mutex>

 #include "opentelemetry/context/propagation/noop_propagator.h"
+#include "opentelemetry/context/propagation/text_map_propagator.h"

-#include "opentelemetry/common/macros.h"
 #include "opentelemetry/common/spin_lock_mutex.h"
 #include "opentelemetry/nostd/shared_ptr.h"

@ -19,11 +19,9 @@ namespace context
 namespace propagation
 {

-class TextMapPropagator;
-
 /* Stores the singleton TextMapPropagator */

-class OPENTELEMETRY_EXPORT GlobalTextMapPropagator
+class GlobalTextMapPropagator
 {
 public:
  static nostd::shared_ptr<TextMapPropagator> GetGlobalPropagator() noexcept
@ -32,20 +30,20 @@ public:
    return nostd::shared_ptr<TextMapPropagator>(GetPropagator());
  }

-  static void SetGlobalPropagator(const nostd::shared_ptr<TextMapPropagator> &prop) noexcept
+  static void SetGlobalPropagator(nostd::shared_ptr<TextMapPropagator> prop) noexcept
  {
    std::lock_guard<common::SpinLockMutex> guard(GetLock());
    GetPropagator() = prop;
  }

 private:
-  OPENTELEMETRY_API_SINGLETON static nostd::shared_ptr<TextMapPropagator> &GetPropagator() noexcept
+  static nostd::shared_ptr<TextMapPropagator> &GetPropagator() noexcept
  {
    static nostd::shared_ptr<TextMapPropagator> propagator(new NoOpPropagator());
    return propagator;
  }

-  OPENTELEMETRY_API_SINGLETON static common::SpinLockMutex &GetLock() noexcept
+  static common::SpinLockMutex &GetLock() noexcept
  {
    static common::SpinLockMutex lock;
    return lock;
@ -54,4 +52,4 @@ private:

 }  // namespace propagation
 }  // namespace context
-OPENTELEMETRY_END_NAMESPACE
+OPENTELEMETRY_END_NAMESPACE
--- a/api/include/opentelemetry/context/propagation/noop_propagator.h
+++ b/api/include/opentelemetry/context/propagation/noop_propagator.h
@ -26,15 +26,13 @@ public:
  }

  /** Noop inject function does nothing */
-  void Inject(TextMapCarrier & /*carrier*/,
-              const context::Context & /* context */) noexcept override
-  {}
+  void Inject(TextMapCarrier & /*carrier*/, const context::Context &context) noexcept override {}

-  bool Fields(nostd::function_ref<bool(nostd::string_view)> /* callback */) const noexcept override
+  bool Fields(nostd::function_ref<bool(nostd::string_view)> callback) const noexcept override
  {
    return true;
  }
 };
 }  // namespace propagation
 }  // namespace context
-OPENTELEMETRY_END_NAMESPACE
+OPENTELEMETRY_END_NAMESPACE
--- a/api/include/opentelemetry/context/propagation/text_map_propagator.h
+++ b/api/include/opentelemetry/context/propagation/text_map_propagator.h
@ -3,8 +3,8 @@

 #pragma once

+#include <cstdint>
 #include "opentelemetry/context/context.h"
-#include "opentelemetry/nostd/function_ref.h"
 #include "opentelemetry/nostd/string_view.h"
 #include "opentelemetry/version.h"

@ -26,7 +26,7 @@ public:

  /* list of all the keys in the carrier.
   By default, it returns true without invoking callback */
-  virtual bool Keys(nostd::function_ref<bool(nostd::string_view)> /* callback */) const noexcept
+  virtual bool Keys(nostd::function_ref<bool(nostd::string_view)> callback) const noexcept
  {
    return true;
  }
--- a/api/include/opentelemetry/context/runtime_context.h
+++ b/api/include/opentelemetry/context/runtime_context.h
@ -1,18 +1,9 @@
-// Copyright The OpenTelemetry Authors
+// Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0

 #pragma once

-#include <stddef.h>
-#include <algorithm>
-
-#include "opentelemetry/common/macros.h"
 #include "opentelemetry/context/context.h"
-#include "opentelemetry/context/context_value.h"
-#include "opentelemetry/nostd/shared_ptr.h"
-#include "opentelemetry/nostd/string_view.h"
-#include "opentelemetry/nostd/unique_ptr.h"
-#include "opentelemetry/version.h"

 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace context
@ -26,11 +17,13 @@ class Token
 public:
  bool operator==(const Context &other) const noexcept { return context_ == other; }

-  ~Token() noexcept;
+  ~Token();

 private:
  friend class RuntimeContextStorage;

+  Token() noexcept = default;
+
  // A constructor that sets the token's Context object to the
  // one that was passed in.
  Token(const Context &context) : context_(context) {}
@ -45,7 +38,7 @@ private:
 * this class and passing an initialized RuntimeContextStorage object to
 * RuntimeContext::SetRuntimeContextStorage.
 */
-class OPENTELEMETRY_EXPORT RuntimeContextStorage
+class RuntimeContextStorage
 {
 public:
  /**
@ -56,7 +49,7 @@ public:

  /**
   * Set the current context.
-   * @param context The new current context
+   * @param the new current context
   * @return a token for the new current context. This never returns a nullptr.
   */
  virtual nostd::unique_ptr<Token> Attach(const Context &context) noexcept = 0;
@ -68,7 +61,7 @@ public:
   */
  virtual bool Detach(Token &token) noexcept = 0;

-  virtual ~RuntimeContextStorage() {}
+  virtual ~RuntimeContextStorage(){};

 protected:
  nostd::unique_ptr<Token> CreateToken(const Context &context) noexcept
@ -86,7 +79,7 @@ static RuntimeContextStorage *GetDefaultStorage() noexcept;
 // Provides a wrapper for propagating the context object globally.
 //
 // By default, a thread-local runtime context storage is used.
-class OPENTELEMETRY_EXPORT RuntimeContext
+class RuntimeContext
 {
 public:
  // Return the current context.
@ -152,38 +145,25 @@ public:
   *
   * @param storage a custom runtime context storage
   */
-  static void SetRuntimeContextStorage(
-      const nostd::shared_ptr<RuntimeContextStorage> &storage) noexcept
+  static void SetRuntimeContextStorage(nostd::shared_ptr<RuntimeContextStorage> storage) noexcept
  {
    GetStorage() = storage;
  }

-  /**
-   * Provide a pointer to const runtime context storage.
-   *
-   * The returned pointer can only be used for extending the lifetime of the runtime context
-   * storage.
-   *
-   */
-  static nostd::shared_ptr<const RuntimeContextStorage> GetConstRuntimeContextStorage() noexcept
-  {
-    return GetRuntimeContextStorage();
-  }
-
 private:
  static nostd::shared_ptr<RuntimeContextStorage> GetRuntimeContextStorage() noexcept
  {
    return GetStorage();
  }

-  OPENTELEMETRY_API_SINGLETON static nostd::shared_ptr<RuntimeContextStorage> &GetStorage() noexcept
+  static nostd::shared_ptr<RuntimeContextStorage> &GetStorage() noexcept
  {
    static nostd::shared_ptr<RuntimeContextStorage> context(GetDefaultStorage());
    return context;
  }
 };

-inline Token::~Token() noexcept
+inline Token::~Token()
 {
  context::RuntimeContext::Detach(*this);
 }
@ -241,7 +221,7 @@ private:
  {
    friend class ThreadLocalContextStorage;

-    Stack() noexcept : size_(0), capacity_(0), base_(nullptr) {}
+    Stack() noexcept : size_(0), capacity_(0), base_(nullptr){};

    // Pops the top Context off the stack.
    void Pop() noexcept
@ -325,7 +305,7 @@ private:
    Context *base_;
  };

-  OPENTELEMETRY_API_SINGLETON Stack &GetStack()
+  Stack &GetStack()
  {
    static thread_local Stack stack_ = Stack();
    return stack_;
--- a/api/include/opentelemetry/detail/preprocessor.h
+++ b/api/include/opentelemetry/detail/preprocessor.h
@ -11,15 +11,3 @@

 #define OPENTELEMETRY_CONCAT(A, B) OPENTELEMETRY_CONCAT_(A, B)
 #define OPENTELEMETRY_CONCAT_(A, B) A##B
-
-// Import the C++20 feature-test macros
-#ifdef __has_include
-#  if __has_include(<version>)
-#    include <version>
-#  endif
-#elif defined(_MSC_VER) && ((defined(__cplusplus) && __cplusplus >= 202002L) || \
-                            (defined(_MSVC_LANG) && _MSVC_LANG >= 202002L))
-#  if _MSC_VER >= 1922
-#    include <version>
-#  endif
-#endif
--- a/api/include/opentelemetry/logs/event_id.h
+++ b/api/include/opentelemetry/logs/event_id.h
@ -1,37 +0,0 @@
-// Copyright The OpenTelemetry Authors
-// SPDX-License-Identifier: Apache-2.0
-
-#pragma once
-
-#include <algorithm>
-
-#include "opentelemetry/nostd/string_view.h"
-#include "opentelemetry/nostd/unique_ptr.h"
-#include "opentelemetry/version.h"
-
-OPENTELEMETRY_BEGIN_NAMESPACE
-namespace logs
-{
-
-/**
- * EventId class which acts the Id of the event with an optional name.
- */
-class EventId
-{
-public:
-  EventId(int64_t id, nostd::string_view name) noexcept
-      : id_{id}, name_{nostd::unique_ptr<char[]>{new char[name.length() + 1]}}
-  {
-    std::copy(name.begin(), name.end(), name_.get());
-    name_.get()[name.length()] = 0;
-  }
-
-  EventId(int64_t id) noexcept : id_{id}, name_{nullptr} {}
-
-public:
-  int64_t id_;
-  nostd::unique_ptr<char[]> name_;
-};
-
-}  // namespace logs
-OPENTELEMETRY_END_NAMESPACE
--- a/api/include/opentelemetry/logs/event_logger.h
+++ b/api/include/opentelemetry/logs/event_logger.h
@ -1,82 +0,0 @@
-// Copyright The OpenTelemetry Authors
-// SPDX-License-Identifier: Apache-2.0
-
-#pragma once
-
-#include "opentelemetry/logs/log_record.h"
-#include "opentelemetry/logs/logger.h"
-#include "opentelemetry/logs/logger_type_traits.h"
-#include "opentelemetry/nostd/shared_ptr.h"
-#include "opentelemetry/nostd/string_view.h"
-#include "opentelemetry/nostd/unique_ptr.h"
-#include "opentelemetry/version.h"
-
-OPENTELEMETRY_BEGIN_NAMESPACE
-namespace logs
-{
-#if OPENTELEMETRY_ABI_VERSION_NO < 2
-/**
- * Handles event log record creation.
- **/
-class OPENTELEMETRY_DEPRECATED EventLogger
-{
-public:
-  virtual ~EventLogger() = default;
-
-  /* Returns the name of the logger */
-  virtual const nostd::string_view GetName() noexcept = 0;
-
-  /* Returns the delegate logger of this event logger */
-  virtual nostd::shared_ptr<Logger> GetDelegateLogger() noexcept = 0;
-
-  /**
-   * Emit a event Log Record object
-   *
-   * @param event_name Event name
-   * @param log_record Log record
-   */
-  virtual void EmitEvent(nostd::string_view event_name,
-                         nostd::unique_ptr<LogRecord> &&log_record) noexcept = 0;
-
-  /**
-   * Emit a event Log Record object with arguments
-   *
-   * @param event_name Event name
-   * @param args Arguments which can be used to set data of log record by type.
-   *  Severity                                -> severity, severity_text
-   *  string_view                             -> body
-   *  AttributeValue                          -> body
-   *  SpanContext                             -> span_id,tace_id and trace_flags
-   *  SpanId                                  -> span_id
-   *  TraceId                                 -> tace_id
-   *  TraceFlags                              -> trace_flags
-   *  SystemTimestamp                         -> timestamp
-   *  system_clock::time_point                -> timestamp
-   *  KeyValueIterable                        -> attributes
-   *  Key value iterable container            -> attributes
-   *  span<pair<string_view, AttributeValue>> -> attributes(return type of MakeAttributes)
-   */
-  template <class... ArgumentType>
-  void EmitEvent(nostd::string_view event_name, ArgumentType &&...args)
-  {
-    nostd::shared_ptr<Logger> delegate_logger = GetDelegateLogger();
-    if (!delegate_logger)
-    {
-      return;
-    }
-    nostd::unique_ptr<LogRecord> log_record = delegate_logger->CreateLogRecord();
-
-    IgnoreTraitResult(detail::LogRecordSetterTrait<typename std::decay<ArgumentType>::type>::Set(
-        log_record.get(), std::forward<ArgumentType>(args))...);
-
-    EmitEvent(event_name, std::move(log_record));
-  }
-
-private:
-  template <class... ValueType>
-  void IgnoreTraitResult(ValueType &&...)
-  {}
-};
-#endif
-}  // namespace logs
-OPENTELEMETRY_END_NAMESPACE
--- a/api/include/opentelemetry/logs/event_logger_provider.h
+++ b/api/include/opentelemetry/logs/event_logger_provider.h
@ -1,37 +0,0 @@
-// Copyright The OpenTelemetry Authors
-// SPDX-License-Identifier: Apache-2.0
-
-#pragma once
-
-#include "opentelemetry/nostd/shared_ptr.h"
-#include "opentelemetry/nostd/string_view.h"
-#include "opentelemetry/version.h"
-
-OPENTELEMETRY_BEGIN_NAMESPACE
-namespace logs
-{
-
-class EventLogger;
-class Logger;
-
-#if OPENTELEMETRY_ABI_VERSION_NO < 2
-/**
- * Creates new EventLogger instances.
- */
-class OPENTELEMETRY_DEPRECATED EventLoggerProvider
-{
-public:
-  virtual ~EventLoggerProvider() = default;
-
-  /**
-   * Creates a named EventLogger instance.
-   *
-   */
-
-  virtual nostd::shared_ptr<EventLogger> CreateEventLogger(
-      nostd::shared_ptr<Logger> delegate_logger,
-      nostd::string_view event_domain) noexcept = 0;
-};
-#endif
-}  // namespace logs
-OPENTELEMETRY_END_NAMESPACE
--- a/api/include/opentelemetry/logs/log_record.h
+++ b/api/include/opentelemetry/logs/log_record.h
@ -1,92 +0,0 @@
-// Copyright The OpenTelemetry Authors
-// SPDX-License-Identifier: Apache-2.0
-
-#pragma once
-
-#include "opentelemetry/common/attribute_value.h"
-#include "opentelemetry/common/timestamp.h"
-#include "opentelemetry/version.h"
-
-OPENTELEMETRY_BEGIN_NAMESPACE
-namespace trace
-{
-class SpanId;
-class TraceId;
-class TraceFlags;
-}  // namespace trace
-
-namespace logs
-{
-
-enum class Severity : uint8_t;
-
-/**
- * Maintains a representation of a log in a format that can be processed by a recorder.
- *
- * This class is thread-compatible.
- */
-class LogRecord
-{
-public:
-  virtual ~LogRecord() = default;
-
-  /**
-   * Set the timestamp for this log.
-   * @param timestamp the timestamp to set
-   */
-  virtual void SetTimestamp(common::SystemTimestamp timestamp) noexcept = 0;
-
-  /**
-   * Set the observed timestamp for this log.
-   * @param timestamp the timestamp to set
-   */
-  virtual void SetObservedTimestamp(common::SystemTimestamp timestamp) noexcept = 0;
-
-  /**
-   * Set the severity for this log.
-   * @param severity the severity of the event
-   */
-  virtual void SetSeverity(logs::Severity severity) noexcept = 0;
-
-  /**
-   * Set body field for this log.
-   * @param message the body to set
-   */
-  virtual void SetBody(const common::AttributeValue &message) noexcept = 0;
-
-  /**
-   * Set an attribute of a log.
-   * @param key the name of the attribute
-   * @param value the attribute value
-   */
-  virtual void SetAttribute(nostd::string_view key,
-                            const common::AttributeValue &value) noexcept = 0;
-
-  /**
-   * Set the Event Id.
-   * @param id The event id to set
-   * @param name Optional event name to set
-   */
-  // TODO: mark this as pure virtual once all exporters have been updated
-  virtual void SetEventId(int64_t id, nostd::string_view name = {}) noexcept = 0;
-
-  /**
-   * Set the trace id for this log.
-   * @param trace_id the trace id to set
-   */
-  virtual void SetTraceId(const trace::TraceId &trace_id) noexcept = 0;
-
-  /**
-   * Set the span id for this log.
-   * @param span_id the span id to set
-   */
-  virtual void SetSpanId(const trace::SpanId &span_id) noexcept = 0;
-
-  /**
-   * Inject trace_flags for this log.
-   * @param trace_flags the trace flags to set
-   */
-  virtual void SetTraceFlags(const trace::TraceFlags &trace_flags) noexcept = 0;
-};
-}  // namespace logs
-OPENTELEMETRY_END_NAMESPACE
--- a/api/include/opentelemetry/logs/logger.h
+++ b/api/include/opentelemetry/logs/logger.h
@ -2,25 +2,29 @@
 // SPDX-License-Identifier: Apache-2.0

 #pragma once
+#ifdef ENABLE_LOGS_PREVIEW

-#include "opentelemetry/logs/logger_type_traits.h"
-#include "opentelemetry/logs/severity.h"
-#include "opentelemetry/nostd/string_view.h"
-#include "opentelemetry/nostd/unique_ptr.h"
-#include "opentelemetry/version.h"
+#  include <chrono>
+#  include <map>
+#  include <vector>
+
+#  include "opentelemetry/common/attribute_value.h"
+#  include "opentelemetry/common/key_value_iterable.h"
+#  include "opentelemetry/common/key_value_iterable_view.h"
+#  include "opentelemetry/common/timestamp.h"
+#  include "opentelemetry/logs/severity.h"
+#  include "opentelemetry/nostd/shared_ptr.h"
+#  include "opentelemetry/nostd/span.h"
+#  include "opentelemetry/nostd/string_view.h"
+#  include "opentelemetry/nostd/type_traits.h"
+#  include "opentelemetry/trace/span_id.h"
+#  include "opentelemetry/trace/trace_flags.h"
+#  include "opentelemetry/trace/trace_id.h"
+#  include "opentelemetry/version.h"

 OPENTELEMETRY_BEGIN_NAMESPACE
-namespace common
-{
-class KeyValueIterable;
-}  // namespace common
-
 namespace logs
 {
-
-class EventId;
-class LogRecord;
-
 /**
 * Handles log record creation.
 **/
@ -33,460 +37,553 @@ public:
  virtual const nostd::string_view GetName() noexcept = 0;

  /**
-   * Create a Log Record object
+   * Each of the following overloaded Log(...) methods
+   * creates a log message with the specific parameters passed.
   *
-   * @return nostd::unique_ptr<LogRecord>
+   * @param severity the severity level of the log event.
+   * @param name the name of the log event.
+   * @param message the string message of the log (perhaps support std::fmt or fmt-lib format).
+   * @param resource the resources, stored as a 2D list of key/value pairs, that are associated
+   * with the log event.
+   * @param attributes the attributes, stored as a 2D list of key/value pairs, that are associated
+   * with the log event.
+   * @param trace_id the trace id associated with the log event.
+   * @param span_id the span id associate with the log event.
+   * @param trace_flags the trace flags associated with the log event.
+   * @param timestamp the timestamp the log record was created.
+   * @throws No exceptions under any circumstances.
   */
-  virtual nostd::unique_ptr<LogRecord> CreateLogRecord() noexcept = 0;

  /**
-   * Emit a Log Record object
+   * The base Log(...) method that all other Log(...) overloaded methods will eventually call,
+   * in order to create a log record.
   *
-   * @param log_record Log record
+   * Note this takes in a KeyValueIterable for the resource and attributes fields.
   */
-  virtual void EmitLogRecord(nostd::unique_ptr<LogRecord> &&log_record) noexcept = 0;
+  virtual void Log(Severity severity,
+                   nostd::string_view name,
+                   nostd::string_view body,
+                   const common::KeyValueIterable &resource,
+                   const common::KeyValueIterable &attributes,
+                   trace::TraceId trace_id,
+                   trace::SpanId span_id,
+                   trace::TraceFlags trace_flags,
+                   common::SystemTimestamp timestamp) noexcept = 0;

+  /*** Overloaded methods for KeyValueIterables ***/
  /**
-   * Emit a Log Record object with arguments
+   * The secondary base Log(...) method that all other Log(...) overloaded methods except the one
+   * above will eventually call,  in order to create a log record.
   *
-   * @param log_record Log record
-   * @param args Arguments which can be used to set data of log record by type.
-   *  Severity                                -> severity, severity_text
-   *  string_view                             -> body
-   *  AttributeValue                          -> body
-   *  SpanContext                             -> span_id,trace_id and trace_flags
-   *  SpanId                                  -> span_id
-   *  TraceId                                 -> trace_id
-   *  TraceFlags                              -> trace_flags
-   *  SystemTimestamp                         -> timestamp
-   *  system_clock::time_point                -> timestamp
-   *  KeyValueIterable                        -> attributes
-   *  Key value iterable container            -> attributes
-   *  span<pair<string_view, AttributeValue>> -> attributes(return type of MakeAttributes)
+   * Note this takes in template types for the resource and attributes fields.
   */
-  template <class... ArgumentType>
-  void EmitLogRecord(nostd::unique_ptr<LogRecord> &&log_record, ArgumentType &&...args)
+  template <class T,
+            class U,
+            nostd::enable_if_t<common::detail::is_key_value_iterable<T>::value> * = nullptr,
+            nostd::enable_if_t<common::detail::is_key_value_iterable<U>::value> * = nullptr>
+  void Log(Severity severity,
+           nostd::string_view name,
+           nostd::string_view body,
+           const T &resource,
+           const U &attributes,
+           trace::TraceId trace_id,
+           trace::SpanId span_id,
+           trace::TraceFlags trace_flags,
+           common::SystemTimestamp timestamp) noexcept
  {
-    if (!log_record)
-    {
-      return;
-    }
+    Log(severity, name, body, common::KeyValueIterableView<T>(resource),
+        common::KeyValueIterableView<U>(attributes), trace_id, span_id, trace_flags, timestamp);
+  }

-    //
-    // Keep the parameter pack unpacking order from left to right because left
-    // ones are usually more important like severity and event_id than the
-    // attributes. The left to right unpack order could pass the more important
-    // data to processors to avoid caching and memory allocating.
-    //
-#if __cplusplus <= 201402L
-    // C++14 does not support fold expressions for parameter pack expansion.
-    int dummy[] = {(detail::LogRecordSetterTrait<typename std::decay<ArgumentType>::type>::Set(
-                        log_record.get(), std::forward<ArgumentType>(args)),
-                    0)...};
-    IgnoreTraitResult(dummy);
-#else
-    IgnoreTraitResult((detail::LogRecordSetterTrait<typename std::decay<ArgumentType>::type>::Set(
-                           log_record.get(), std::forward<ArgumentType>(args)),
-                       ...));
-#endif
+  void Log(Severity severity,
+           nostd::string_view name,
+           nostd::string_view body,
+           std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>> resource,
+           std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>> attributes,
+           trace::TraceId trace_id,
+           trace::SpanId span_id,
+           trace::TraceFlags trace_flags,
+           common::SystemTimestamp timestamp) noexcept
+  {
+    return this->Log(severity, name, body,
+                     nostd::span<const std::pair<nostd::string_view, common::AttributeValue>>{
+                         resource.begin(), resource.end()},
+                     nostd::span<const std::pair<nostd::string_view, common::AttributeValue>>{
+                         attributes.begin(), attributes.end()},
+                     trace_id, span_id, trace_flags, timestamp);
+  }

-    EmitLogRecord(std::move(log_record));
+  /** Wrapper methods that the user could call for convenience when logging **/
+
+  /**
+   * Writes a log.
+   * @param severity The severity of the log
+   * @param message The message to log
+   */
+  void Log(Severity severity, nostd::string_view message) noexcept
+  {
+    this->Log(severity, "", message, {}, {}, {}, {}, {}, std::chrono::system_clock::now());
  }

  /**
-   * Emit a Log Record object with arguments
-   *
-   * @param args Arguments which can be used to set data of log record by type.
-   *  Severity                                -> severity, severity_text
-   *  string_view                             -> body
-   *  AttributeValue                          -> body
-   *  SpanContext                             -> span_id,trace_id and trace_flags
-   *  SpanId                                  -> span_id
-   *  TraceId                                 -> trace_id
-   *  TraceFlags                              -> trace_flags
-   *  SystemTimestamp                         -> timestamp
-   *  system_clock::time_point                -> timestamp
-   *  KeyValueIterable                        -> attributes
-   *  Key value iterable container            -> attributes
-   *  span<pair<string_view, AttributeValue>> -> attributes(return type of MakeAttributes)
+   * Writes a log.
+   * @param severity The severity of the log
+   * @param name The name of the log
+   * @param message The message to log
   */
-  template <class... ArgumentType>
-  void EmitLogRecord(ArgumentType &&...args)
+  void Log(Severity severity, nostd::string_view name, nostd::string_view message) noexcept
  {
-    nostd::unique_ptr<LogRecord> log_record = CreateLogRecord();
+    this->Log(severity, name, message, {}, {}, {}, {}, {}, std::chrono::system_clock::now());
+  }

-    EmitLogRecord(std::move(log_record), std::forward<ArgumentType>(args)...);
+  /**
+   * Writes a log.
+   * @param severity The severity of the log
+   * @param attributes The attributes of the log as a key/value object
+   */
+  template <class T,
+            nostd::enable_if_t<common::detail::is_key_value_iterable<T>::value> * = nullptr>
+  void Log(Severity severity, const T &attributes) noexcept
+  {
+    this->Log(severity, "", "", std::map<std::string, std::string>{}, attributes, {}, {}, {},
+              std::chrono::system_clock::now());
+  }
+
+  /**
+   * Writes a log.
+   * @param severity The severity of the log
+   * @param name The name of the log
+   * @param attributes The attributes of the log as a key/value object
+   */
+  template <class T,
+            nostd::enable_if_t<common::detail::is_key_value_iterable<T>::value> * = nullptr>
+  void Log(Severity severity, nostd::string_view name, const T &attributes) noexcept
+  {
+    this->Log(severity, name, "", std::map<std::string, std::string>{}, attributes, {}, {}, {},
+              std::chrono::system_clock::now());
+  }
+
+  /**
+   * Writes a log.
+   * @param severity The severity of the log
+   * @param attributes The attributes of the log as an initializer list
+   */
+  void Log(Severity severity,
+           std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>>
+               attributes) noexcept
+  {
+    this->Log(severity, "", "", {}, attributes, {}, {}, {}, std::chrono::system_clock::now());
+  }
+
+  /**
+   * Writes a log.
+   * @param severity The severity of the log
+   * @param name The name of the log
+   * @param attributes The attributes of the log as an initializer list
+   */
+  void Log(Severity severity,
+           nostd::string_view name,
+           std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>>
+               attributes) noexcept
+  {
+    this->Log(severity, name, "", {}, attributes, {}, {}, {}, std::chrono::system_clock::now());
+  }
+
+  /**
+   * Writes a log.
+   * @param severity The severity of the log
+   * @param name The name of the log
+   * @param attributes The attributes, stored as a 2D list of key/value pairs, that are associated
+   * with the log event
+   */
+  void Log(Severity severity,
+           nostd::string_view name,
+           common::KeyValueIterable &attributes) noexcept
+  {
+    this->Log(severity, name, {},
+              common::KeyValueIterableView<
+                  std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>>>({}),
+              attributes, {}, {}, {}, std::chrono::system_clock::now());
+  }
+
+  /** Trace severity overloads **/
+
+  /**
+   * Writes a log with a severity of trace.
+   * @param message The message to log
+   */
+  void Trace(nostd::string_view message) noexcept { this->Log(Severity::kTrace, message); }
+
+  /**
+   * Writes a log with a severity of trace.
+   * @param name The name of the log
+   * @param message The message to log
+   */
+  void Trace(nostd::string_view name, nostd::string_view message) noexcept
+  {
+    this->Log(Severity::kTrace, name, message);
  }

  /**
   * Writes a log with a severity of trace.
-   * @param args Arguments which can be used to set data of log record by type.
-   *  string_view                             -> body
-   *  AttributeValue                          -> body
-   *  SpanContext                             -> span_id,trace_id and trace_flags
-   *  SpanId                                  -> span_id
-   *  TraceId                                 -> trace_id
-   *  TraceFlags                              -> trace_flags
-   *  SystemTimestamp                         -> timestamp
-   *  system_clock::time_point                -> timestamp
-   *  KeyValueIterable                        -> attributes
-   *  Key value iterable container            -> attributes
-   *  span<pair<string_view, AttributeValue>> -> attributes(return type of MakeAttributes)
+   * @param attributes The attributes of the log as a key/value object
   */
-  template <class... ArgumentType>
-  void Trace(ArgumentType &&...args) noexcept
+  template <class T,
+            nostd::enable_if_t<common::detail::is_key_value_iterable<T>::value> * = nullptr>
+  void Trace(const T &attributes) noexcept
  {
-    static_assert(
-        !detail::LogRecordHasType<Severity, typename std::decay<ArgumentType>::type...>::value,
-        "Severity is already set.");
-    this->EmitLogRecord(Severity::kTrace, std::forward<ArgumentType>(args)...);
+    this->Log(Severity::kTrace, attributes);
+  }
+
+  /**
+   * Writes a log with a severity of trace.
+   * @param name The name of the log
+   * @param attributes The attributes of the log as a key/value object
+   */
+  template <class T,
+            nostd::enable_if_t<common::detail::is_key_value_iterable<T>::value> * = nullptr>
+  void Trace(nostd::string_view name, const T &attributes) noexcept
+  {
+    this->Log(Severity::kTrace, name, attributes);
+  }
+
+  /**
+   * Writes a log with a severity of trace.
+   * @param attributes The attributes of the log as an initializer list
+   */
+  void Trace(std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>>
+                 attributes) noexcept
+  {
+    this->Log(Severity::kTrace, attributes);
+  }
+
+  /**
+   * Writes a log with a severity of trace.
+   * @param name The name of the log
+   * @param attributes The attributes of the log as an initializer list
+   */
+  void Trace(nostd::string_view name,
+             std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>>
+                 attributes) noexcept
+  {
+    this->Log(Severity::kTrace, name, attributes);
+  }
+
+  /** Debug severity overloads **/
+
+  /**
+   * Writes a log with a severity of debug.
+   * @param message The message to log
+   */
+  void Debug(nostd::string_view message) noexcept { this->Log(Severity::kDebug, message); }
+
+  /**
+   * Writes a log with a severity of debug.
+   * @param name The name of the log
+   * @param message The message to log
+   */
+  void Debug(nostd::string_view name, nostd::string_view message) noexcept
+  {
+    this->Log(Severity::kDebug, name, message);
  }

  /**
   * Writes a log with a severity of debug.
-   * @param args Arguments which can be used to set data of log record by type.
-   *  string_view                             -> body
-   *  AttributeValue                          -> body
-   *  SpanContext                             -> span_id,trace_id and trace_flags
-   *  SpanId                                  -> span_id
-   *  TraceId                                 -> trace_id
-   *  TraceFlags                              -> trace_flags
-   *  SystemTimestamp                         -> timestamp
-   *  system_clock::time_point                -> timestamp
-   *  KeyValueIterable                        -> attributes
-   *  Key value iterable container            -> attributes
-   *  span<pair<string_view, AttributeValue>> -> attributes(return type of MakeAttributes)
+   * @param attributes The attributes of the log as a key/value object
   */
-  template <class... ArgumentType>
-  void Debug(ArgumentType &&...args) noexcept
+  template <class T,
+            nostd::enable_if_t<common::detail::is_key_value_iterable<T>::value> * = nullptr>
+  void Debug(const T &attributes) noexcept
  {
-    static_assert(
-        !detail::LogRecordHasType<Severity, typename std::decay<ArgumentType>::type...>::value,
-        "Severity is already set.");
-    this->EmitLogRecord(Severity::kDebug, std::forward<ArgumentType>(args)...);
+    this->Log(Severity::kDebug, attributes);
+  }
+
+  /**
+   * Writes a log with a severity of debug.
+   * @param name The name of the log
+   * @param attributes The attributes of the log as a key/value object
+   */
+  template <class T,
+            nostd::enable_if_t<common::detail::is_key_value_iterable<T>::value> * = nullptr>
+  void Debug(nostd::string_view name, const T &attributes) noexcept
+  {
+    this->Log(Severity::kDebug, name, attributes);
+  }
+
+  /**
+   * Writes a log with a severity of debug.
+   * @param attributes The attributes of the log as an initializer list
+   */
+  void Debug(std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>>
+                 attributes) noexcept
+  {
+    this->Log(Severity::kDebug, attributes);
+  }
+
+  /**
+   * Writes a log with a severity of debug.
+   * @param name The name of the log
+   * @param attributes The attributes of the log as an initializer list
+   */
+  void Debug(nostd::string_view name,
+             std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>>
+                 attributes) noexcept
+  {
+    this->Log(Severity::kDebug, name, attributes);
+  }
+
+  /** Info severity overloads **/
+
+  /**
+   * Writes a log with a severity of info.
+   * @param message The message to log
+   */
+  void Info(nostd::string_view message) noexcept { this->Log(Severity::kInfo, message); }
+
+  /**
+   * Writes a log with a severity of info.
+   * @param name The name of the log
+   * @param message The message to log
+   */
+  void Info(nostd::string_view name, nostd::string_view message) noexcept
+  {
+    this->Log(Severity::kInfo, name, message);
  }

  /**
   * Writes a log with a severity of info.
-   * @param args Arguments which can be used to set data of log record by type.
-   *  string_view                             -> body
-   *  AttributeValue                          -> body
-   *  SpanContext                             -> span_id,trace_id and trace_flags
-   *  SpanId                                  -> span_id
-   *  TraceId                                 -> trace_id
-   *  TraceFlags                              -> trace_flags
-   *  SystemTimestamp                         -> timestamp
-   *  system_clock::time_point                -> timestamp
-   *  KeyValueIterable                        -> attributes
-   *  Key value iterable container            -> attributes
-   *  span<pair<string_view, AttributeValue>> -> attributes(return type of MakeAttributes)
+   * @param attributes The attributes of the log as a key/value object
   */
-  template <class... ArgumentType>
-  void Info(ArgumentType &&...args) noexcept
+  template <class T,
+            nostd::enable_if_t<common::detail::is_key_value_iterable<T>::value> * = nullptr>
+  void Info(const T &attributes) noexcept
  {
-    static_assert(
-        !detail::LogRecordHasType<Severity, typename std::decay<ArgumentType>::type...>::value,
-        "Severity is already set.");
-    this->EmitLogRecord(Severity::kInfo, std::forward<ArgumentType>(args)...);
+    this->Log(Severity::kInfo, attributes);
+  }
+
+  /**
+   * Writes a log with a severity of info.
+   * @param name The name of the log
+   * @param attributes The attributes of the log as a key/value object
+   */
+  template <class T,
+            nostd::enable_if_t<common::detail::is_key_value_iterable<T>::value> * = nullptr>
+  void Info(nostd::string_view name, const T &attributes) noexcept
+  {
+    this->Log(Severity::kInfo, name, attributes);
+  }
+
+  /**
+   * Writes a log with a severity of info.
+   * @param attributes The attributes of the log as an initializer list
+   */
+  void Info(std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>>
+                attributes) noexcept
+  {
+    this->Log(Severity::kInfo, attributes);
+  }
+
+  /**
+   * Writes a log with a severity of info.
+   * @param name The name of the log
+   * @param attributes The attributes of the log as an initializer list
+   */
+  void Info(nostd::string_view name,
+            std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>>
+                attributes) noexcept
+  {
+    this->Log(Severity::kInfo, name, attributes);
+  }
+
+  /** Warn severity overloads **/
+
+  /**
+   * Writes a log with a severity of warn.
+   * @param message The message to log
+   */
+  void Warn(nostd::string_view message) noexcept { this->Log(Severity::kWarn, message); }
+
+  /**
+   * Writes a log with a severity of warn.
+   * @param name The name of the log
+   * @param message The message to log
+   */
+  void Warn(nostd::string_view name, nostd::string_view message) noexcept
+  {
+    this->Log(Severity::kWarn, name, message);
  }

  /**
   * Writes a log with a severity of warn.
-   * @param args Arguments which can be used to set data of log record by type.
-   *  string_view                             -> body
-   *  AttributeValue                          -> body
-   *  SpanContext                             -> span_id,trace_id and trace_flags
-   *  SpanId                                  -> span_id
-   *  TraceId                                 -> trace_id
-   *  TraceFlags                              -> trace_flags
-   *  SystemTimestamp                         -> timestamp
-   *  system_clock::time_point                -> timestamp
-   *  KeyValueIterable                        -> attributes
-   *  Key value iterable container            -> attributes
-   *  span<pair<string_view, AttributeValue>> -> attributes(return type of MakeAttributes)
+   * @param attributes The attributes of the log as a key/value object
   */
-  template <class... ArgumentType>
-  void Warn(ArgumentType &&...args) noexcept
+  template <class T,
+            nostd::enable_if_t<common::detail::is_key_value_iterable<T>::value> * = nullptr>
+  void Warn(const T &attributes) noexcept
  {
-    static_assert(
-        !detail::LogRecordHasType<Severity, typename std::decay<ArgumentType>::type...>::value,
-        "Severity is already set.");
-    this->EmitLogRecord(Severity::kWarn, std::forward<ArgumentType>(args)...);
+    this->Log(Severity::kWarn, attributes);
+  }
+
+  /**
+   * Writes a log with a severity of warn.
+   * @param name The name of the log
+   * @param attributes The attributes of the log as a key/value object
+   */
+  template <class T,
+            nostd::enable_if_t<common::detail::is_key_value_iterable<T>::value> * = nullptr>
+  void Warn(nostd::string_view name, const T &attributes) noexcept
+  {
+    this->Log(Severity::kWarn, name, attributes);
+  }
+
+  /**
+   * Writes a log with a severity of warn.
+   * @param attributes The attributes of the log as an initializer list
+   */
+  void Warn(std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>>
+                attributes) noexcept
+  {
+    this->Log(Severity::kWarn, attributes);
+  }
+
+  /**
+   * Writes a log with a severity of warn.
+   * @param name The name of the log
+   * @param attributes The attributes of the log as an initializer list
+   */
+  void Warn(nostd::string_view name,
+            std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>>
+                attributes) noexcept
+  {
+    this->Log(Severity::kWarn, name, attributes);
+  }
+
+  /** Error severity overloads **/
+
+  /**
+   * Writes a log with a severity of error.
+   * @param message The message to log
+   */
+  void Error(nostd::string_view message) noexcept { this->Log(Severity::kError, message); }
+
+  /**
+   * Writes a log with a severity of error.
+   * @param name The name of the log
+   * @param message The message to log
+   */
+  void Error(nostd::string_view name, nostd::string_view message) noexcept
+  {
+    this->Log(Severity::kError, name, message);
  }

  /**
   * Writes a log with a severity of error.
-   * @param args Arguments which can be used to set data of log record by type.
-   *  string_view                             -> body
-   *  AttributeValue                          -> body
-   *  SpanContext                             -> span_id,trace_id and trace_flags
-   *  SpanId                                  -> span_id
-   *  TraceId                                 -> trace_id
-   *  TraceFlags                              -> trace_flags
-   *  SystemTimestamp                         -> timestamp
-   *  system_clock::time_point                -> timestamp
-   *  KeyValueIterable                        -> attributes
-   *  Key value iterable container            -> attributes
-   *  span<pair<string_view, AttributeValue>> -> attributes(return type of MakeAttributes)
+   * @param attributes The attributes of the log as a key/value object
   */
-  template <class... ArgumentType>
-  void Error(ArgumentType &&...args) noexcept
+  template <class T,
+            nostd::enable_if_t<common::detail::is_key_value_iterable<T>::value> * = nullptr>
+  void Error(const T &attributes) noexcept
  {
-    static_assert(
-        !detail::LogRecordHasType<Severity, typename std::decay<ArgumentType>::type...>::value,
-        "Severity is already set.");
-    this->EmitLogRecord(Severity::kError, std::forward<ArgumentType>(args)...);
+    this->Log(Severity::kError, attributes);
+  }
+
+  /**
+   * Writes a log with a severity of error.
+   * @param name The name of the log
+   * @param attributes The attributes of the log as a key/value object
+   */
+  template <class T,
+            nostd::enable_if_t<common::detail::is_key_value_iterable<T>::value> * = nullptr>
+  void Error(nostd::string_view name, const T &attributes) noexcept
+  {
+    this->Log(Severity::kError, name, attributes);
+  }
+
+  /**
+   * Writes a log with a severity of error.
+   * @param attributes The attributes of the log as an initializer list
+   */
+  void Error(std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>>
+                 attributes) noexcept
+  {
+    this->Log(Severity::kError, attributes);
+  }
+
+  /**
+   * Writes a log with a severity of error.
+   * @param name The name of the log
+   * @param attributes The attributes of the log as an initializer list
+   */
+  void Error(nostd::string_view name,
+             std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>>
+                 attributes) noexcept
+  {
+    this->Log(Severity::kError, name, attributes);
+  }
+
+  /** Fatal severity overloads **/
+
+  /**
+   * Writes a log with a severity of fatal.
+   * @param message The message to log
+   */
+  void Fatal(nostd::string_view message) noexcept { this->Log(Severity::kFatal, message); }
+
+  /**
+   * Writes a log with a severity of fatal.
+   * @param name The name of the log
+   * @param message The message to log
+   */
+  void Fatal(nostd::string_view name, nostd::string_view message) noexcept
+  {
+    this->Log(Severity::kFatal, name, message);
  }

  /**
   * Writes a log with a severity of fatal.
-   * @param args Arguments which can be used to set data of log record by type.
-   *  string_view                             -> body
-   *  AttributeValue                          -> body
-   *  SpanContext                             -> span_id,trace_id and trace_flags
-   *  SpanId                                  -> span_id
-   *  TraceId                                 -> trace_id
-   *  TraceFlags                              -> trace_flags
-   *  SystemTimestamp                         -> timestamp
-   *  system_clock::time_point                -> timestamp
-   *  KeyValueIterable                        -> attributes
-   *  Key value iterable container            -> attributes
-   *  span<pair<string_view, AttributeValue>> -> attributes(return type of MakeAttributes)
+   * @param attributes The attributes of the log as a key/value object
   */
-  template <class... ArgumentType>
-  void Fatal(ArgumentType &&...args) noexcept
+  template <class T,
+            nostd::enable_if_t<common::detail::is_key_value_iterable<T>::value> * = nullptr>
+  void Fatal(const T &attributes) noexcept
  {
-    static_assert(
-        !detail::LogRecordHasType<Severity, typename std::decay<ArgumentType>::type...>::value,
-        "Severity is already set.");
-    this->EmitLogRecord(Severity::kFatal, std::forward<ArgumentType>(args)...);
-  }
-
-  //
-  // OpenTelemetry C++ user-facing Logs API
-  //
-
-  inline bool Enabled(Severity severity, const EventId &event_id) const noexcept
-  {
-    if OPENTELEMETRY_LIKELY_CONDITION (!Enabled(severity))
-    {
-      return false;
-    }
-    return EnabledImplementation(severity, event_id);
-  }
-
-  inline bool Enabled(Severity severity, int64_t event_id) const noexcept
-  {
-    if OPENTELEMETRY_LIKELY_CONDITION (!Enabled(severity))
-    {
-      return false;
-    }
-    return EnabledImplementation(severity, event_id);
-  }
-
-  inline bool Enabled(Severity severity) const noexcept
-  {
-    return static_cast<uint8_t>(severity) >= OPENTELEMETRY_ATOMIC_READ_8(&minimum_severity_);
+    this->Log(Severity::kFatal, attributes);
  }

  /**
-   * Log an event
-   *
-   * @severity severity of the log
-   * @event_id event identifier of the log
-   * @format an utf-8 string following https://messagetemplates.org/
-   * @attributes key value pairs of the log
+   * Writes a log with a severity of fatal.
+   * @param name The name of the log
+   * @param attributes The attributes of the log as a key/value object
   */
-  virtual void Log(Severity severity,
-                   const EventId &event_id,
-                   nostd::string_view format,
-                   const common::KeyValueIterable &attributes) noexcept
+  template <class T,
+            nostd::enable_if_t<common::detail::is_key_value_iterable<T>::value> * = nullptr>
+  void Fatal(nostd::string_view name, const T &attributes) noexcept
  {
-    this->EmitLogRecord(severity, event_id, format, attributes);
+    this->Log(Severity::kFatal, name, attributes);
  }

-  virtual void Log(Severity severity,
-                   int64_t event_id,
-                   nostd::string_view format,
-                   const common::KeyValueIterable &attributes) noexcept
+  /**
+   * Writes a log with a severity of fatal.
+   * @param attributes The attributes of the log as an initializer list
+   */
+  void Fatal(std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>>
+                 attributes) noexcept
  {
-    this->EmitLogRecord(severity, EventId{event_id}, format, attributes);
+    this->Log(Severity::kFatal, attributes);
  }

-  virtual void Log(Severity severity,
-                   nostd::string_view format,
-                   const common::KeyValueIterable &attributes) noexcept
+  /**
+   * Writes a log with a severity of fatal.
+   * @param name The name of the log
+   * @param attributes The attributes of the log as an initializer list
+   */
+  void Fatal(nostd::string_view name,
+             std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>>
+                 attributes) noexcept
  {
-    this->EmitLogRecord(severity, format, attributes);
+    this->Log(Severity::kFatal, name, attributes);
  }
-
-  virtual void Log(Severity severity, nostd::string_view message) noexcept
-  {
-    this->EmitLogRecord(severity, message);
-  }
-
-  // Convenient wrappers based on virtual methods Log().
-  // https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/logs/data-model.md#field-severitynumber
-
-  inline void Trace(const EventId &event_id,
-                    nostd::string_view format,
-                    const common::KeyValueIterable &attributes) noexcept
-  {
-    this->Log(Severity::kTrace, event_id, format, attributes);
-  }
-
-  inline void Trace(int64_t event_id,
-                    nostd::string_view format,
-                    const common::KeyValueIterable &attributes) noexcept
-  {
-    this->Log(Severity::kTrace, EventId{event_id}, format, attributes);
-  }
-
-  inline void Trace(nostd::string_view format, const common::KeyValueIterable &attributes) noexcept
-  {
-    this->Log(Severity::kTrace, format, attributes);
-  }
-
-  inline void Trace(nostd::string_view message) noexcept { this->Log(Severity::kTrace, message); }
-
-  inline void Debug(const EventId &event_id,
-                    nostd::string_view format,
-                    const common::KeyValueIterable &attributes) noexcept
-  {
-    this->Log(Severity::kDebug, event_id, format, attributes);
-  }
-
-  inline void Debug(int64_t event_id,
-                    nostd::string_view format,
-                    const common::KeyValueIterable &attributes) noexcept
-  {
-    this->Log(Severity::kDebug, EventId{event_id}, format, attributes);
-  }
-
-  inline void Debug(nostd::string_view format, const common::KeyValueIterable &attributes) noexcept
-  {
-    this->Log(Severity::kDebug, format, attributes);
-  }
-
-  inline void Debug(nostd::string_view message) noexcept { this->Log(Severity::kDebug, message); }
-
-  inline void Info(const EventId &event_id,
-                   nostd::string_view format,
-                   const common::KeyValueIterable &attributes) noexcept
-  {
-    this->Log(Severity::kInfo, event_id, format, attributes);
-  }
-
-  inline void Info(int64_t event_id,
-                   nostd::string_view format,
-                   const common::KeyValueIterable &attributes) noexcept
-  {
-    this->Log(Severity::kInfo, EventId{event_id}, format, attributes);
-  }
-
-  inline void Info(nostd::string_view format, const common::KeyValueIterable &attributes) noexcept
-  {
-    this->Log(Severity::kInfo, format, attributes);
-  }
-
-  inline void Info(nostd::string_view message) noexcept { this->Log(Severity::kInfo, message); }
-
-  inline void Warn(const EventId &event_id,
-                   nostd::string_view format,
-                   const common::KeyValueIterable &attributes) noexcept
-  {
-    this->Log(Severity::kWarn, event_id, format, attributes);
-  }
-
-  inline void Warn(int64_t event_id,
-                   nostd::string_view format,
-                   const common::KeyValueIterable &attributes) noexcept
-  {
-    this->Log(Severity::kWarn, EventId{event_id}, format, attributes);
-  }
-
-  inline void Warn(nostd::string_view format, const common::KeyValueIterable &attributes) noexcept
-  {
-    this->Log(Severity::kWarn, format, attributes);
-  }
-
-  inline void Warn(nostd::string_view message) noexcept { this->Log(Severity::kWarn, message); }
-
-  inline void Error(const EventId &event_id,
-                    nostd::string_view format,
-                    const common::KeyValueIterable &attributes) noexcept
-  {
-    this->Log(Severity::kError, event_id, format, attributes);
-  }
-
-  inline void Error(int64_t event_id,
-                    nostd::string_view format,
-                    const common::KeyValueIterable &attributes) noexcept
-  {
-    this->Log(Severity::kError, EventId{event_id}, format, attributes);
-  }
-
-  inline void Error(nostd::string_view format, const common::KeyValueIterable &attributes) noexcept
-  {
-    this->Log(Severity::kError, format, attributes);
-  }
-
-  inline void Error(nostd::string_view message) noexcept { this->Log(Severity::kError, message); }
-
-  inline void Fatal(const EventId &event_id,
-                    nostd::string_view format,
-                    const common::KeyValueIterable &attributes) noexcept
-  {
-    this->Log(Severity::kFatal, event_id, format, attributes);
-  }
-
-  inline void Fatal(int64_t event_id,
-                    nostd::string_view format,
-                    const common::KeyValueIterable &attributes) noexcept
-  {
-    this->Log(Severity::kFatal, EventId{event_id}, format, attributes);
-  }
-
-  inline void Fatal(nostd::string_view format, const common::KeyValueIterable &attributes) noexcept
-  {
-    this->Log(Severity::kFatal, format, attributes);
-  }
-
-  inline void Fatal(nostd::string_view message) noexcept { this->Log(Severity::kFatal, message); }
-
-  //
-  // End of OpenTelemetry C++ user-facing Log API.
-  //
-
-protected:
-  // TODO: discuss with community about naming for internal methods.
-  virtual bool EnabledImplementation(Severity /*severity*/,
-                                     const EventId & /*event_id*/) const noexcept
-  {
-    return false;
-  }
-
-  virtual bool EnabledImplementation(Severity /*severity*/, int64_t /*event_id*/) const noexcept
-  {
-    return false;
-  }
-
-  void SetMinimumSeverity(uint8_t severity_or_max) noexcept
-  {
-    OPENTELEMETRY_ATOMIC_WRITE_8(&minimum_severity_, severity_or_max);
-  }
-
-private:
-  template <class... ValueType>
-  void IgnoreTraitResult(ValueType &&...)
-  {}
-
-  //
-  // minimum_severity_ can be updated concurrently by multiple threads/cores, so race condition on
-  // read/write should be handled. And std::atomic can not be used here because it is not ABI
-  // compatible for OpenTelemetry C++ API.
-  //
-  mutable uint8_t minimum_severity_{kMaxSeverity};
 };
 }  // namespace logs
 OPENTELEMETRY_END_NAMESPACE
+#endif
--- a/api/include/opentelemetry/logs/logger_provider.h
+++ b/api/include/opentelemetry/logs/logger_provider.h
@ -2,25 +2,19 @@
 // SPDX-License-Identifier: Apache-2.0

 #pragma once
+#ifdef ENABLE_LOGS_PREVIEW

-#include "opentelemetry/common/key_value_iterable.h"
-#include "opentelemetry/common/key_value_iterable_view.h"
-#include "opentelemetry/nostd/shared_ptr.h"
-#include "opentelemetry/nostd/span.h"
-#include "opentelemetry/nostd/string_view.h"
-#include "opentelemetry/nostd/type_traits.h"
-#include "opentelemetry/version.h"
+#  include "opentelemetry/logs/logger.h"
+#  include "opentelemetry/nostd/shared_ptr.h"
+#  include "opentelemetry/nostd/string_view.h"

 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace logs
 {
-
-class Logger;
-
 /**
 * Creates new Logger instances.
 */
-class OPENTELEMETRY_EXPORT LoggerProvider
+class LoggerProvider
 {
 public:
  virtual ~LoggerProvider() = default;
@ -36,36 +30,12 @@ public:
   *
   */

-  virtual nostd::shared_ptr<Logger> GetLogger(
-      nostd::string_view logger_name,
-      nostd::string_view library_name            = "",
-      nostd::string_view library_version         = "",
-      nostd::string_view schema_url              = "",
-      const common::KeyValueIterable &attributes = common::NoopKeyValueIterable()) = 0;
+  virtual nostd::shared_ptr<Logger> GetLogger(nostd::string_view logger_name,
+                                              nostd::string_view options = "") = 0;

-  nostd::shared_ptr<Logger> GetLogger(
-      nostd::string_view logger_name,
-      nostd::string_view library_name,
-      nostd::string_view library_version,
-      nostd::string_view schema_url,
-      std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>> attributes)
-  {
-    return GetLogger(logger_name, library_name, library_version, schema_url,
-                     nostd::span<const std::pair<nostd::string_view, common::AttributeValue>>{
-                         attributes.begin(), attributes.end()});
-  }
-
-  template <class T,
-            nostd::enable_if_t<common::detail::is_key_value_iterable<T>::value> * = nullptr>
-  nostd::shared_ptr<Logger> GetLogger(nostd::string_view logger_name,
-                                      nostd::string_view library_name,
-                                      nostd::string_view library_version,
-                                      nostd::string_view schema_url,
-                                      const T &attributes)
-  {
-    return GetLogger(logger_name, library_name, library_version, schema_url,
-                     common::KeyValueIterableView<T>(attributes));
-  }
+  virtual nostd::shared_ptr<Logger> GetLogger(nostd::string_view logger_name,
+                                              nostd::span<nostd::string_view> args) = 0;
 };
 }  // namespace logs
 OPENTELEMETRY_END_NAMESPACE
+#endif
--- a/api/include/opentelemetry/logs/logger_type_traits.h
+++ b/api/include/opentelemetry/logs/logger_type_traits.h
@ -1,204 +0,0 @@
-// Copyright The OpenTelemetry Authors
-// SPDX-License-Identifier: Apache-2.0
-
-#pragma once
-
-#include <chrono>
-#include <memory>
-#include <type_traits>
-
-#include "opentelemetry/common/attribute_value.h"
-#include "opentelemetry/common/key_value_iterable.h"
-#include "opentelemetry/common/timestamp.h"
-#include "opentelemetry/logs/event_id.h"
-#include "opentelemetry/logs/log_record.h"
-#include "opentelemetry/logs/severity.h"
-#include "opentelemetry/nostd/string_view.h"
-#include "opentelemetry/nostd/type_traits.h"
-#include "opentelemetry/trace/span_context.h"
-#include "opentelemetry/trace/span_id.h"
-#include "opentelemetry/trace/trace_flags.h"
-#include "opentelemetry/trace/trace_id.h"
-#include "opentelemetry/version.h"
-
-OPENTELEMETRY_BEGIN_NAMESPACE
-namespace logs
-{
-namespace detail
-{
-template <class ValueType>
-struct LogRecordSetterTrait;
-
-template <>
-struct LogRecordSetterTrait<Severity>
-{
-  template <class ArgumentType>
-  inline static LogRecord *Set(LogRecord *log_record, ArgumentType &&arg) noexcept
-  {
-    log_record->SetSeverity(std::forward<ArgumentType>(arg));
-
-    return log_record;
-  }
-};
-
-template <>
-struct LogRecordSetterTrait<EventId>
-{
-  template <class ArgumentType>
-  inline static LogRecord *Set(LogRecord *log_record, ArgumentType &&arg) noexcept
-  {
-    log_record->SetEventId(arg.id_, nostd::string_view{arg.name_.get()});
-
-    return log_record;
-  }
-};
-
-template <>
-struct LogRecordSetterTrait<trace::SpanContext>
-{
-  template <class ArgumentType>
-  inline static LogRecord *Set(LogRecord *log_record, ArgumentType &&arg) noexcept
-  {
-    log_record->SetSpanId(arg.span_id());
-    log_record->SetTraceId(arg.trace_id());
-    log_record->SetTraceFlags(arg.trace_flags());
-
-    return log_record;
-  }
-};
-
-template <>
-struct LogRecordSetterTrait<trace::SpanId>
-{
-  template <class ArgumentType>
-  inline static LogRecord *Set(LogRecord *log_record, ArgumentType &&arg) noexcept
-  {
-    log_record->SetSpanId(std::forward<ArgumentType>(arg));
-
-    return log_record;
-  }
-};
-
-template <>
-struct LogRecordSetterTrait<trace::TraceId>
-{
-  template <class ArgumentType>
-  inline static LogRecord *Set(LogRecord *log_record, ArgumentType &&arg) noexcept
-  {
-    log_record->SetTraceId(std::forward<ArgumentType>(arg));
-
-    return log_record;
-  }
-};
-
-template <>
-struct LogRecordSetterTrait<trace::TraceFlags>
-{
-  template <class ArgumentType>
-  inline static LogRecord *Set(LogRecord *log_record, ArgumentType &&arg) noexcept
-  {
-    log_record->SetTraceFlags(std::forward<ArgumentType>(arg));
-
-    return log_record;
-  }
-};
-
-template <>
-struct LogRecordSetterTrait<common::SystemTimestamp>
-{
-  template <class ArgumentType>
-  inline static LogRecord *Set(LogRecord *log_record, ArgumentType &&arg) noexcept
-  {
-    log_record->SetTimestamp(std::forward<ArgumentType>(arg));
-
-    return log_record;
-  }
-};
-
-template <>
-struct LogRecordSetterTrait<std::chrono::system_clock::time_point>
-{
-  template <class ArgumentType>
-  inline static LogRecord *Set(LogRecord *log_record, ArgumentType &&arg) noexcept
-  {
-    log_record->SetTimestamp(common::SystemTimestamp(std::forward<ArgumentType>(arg)));
-
-    return log_record;
-  }
-};
-
-template <>
-struct LogRecordSetterTrait<common::KeyValueIterable>
-{
-  template <class ArgumentType>
-  inline static LogRecord *Set(LogRecord *log_record, ArgumentType &&arg) noexcept
-  {
-    arg.ForEachKeyValue(
-        [&log_record](nostd::string_view key, common::AttributeValue value) noexcept {
-          log_record->SetAttribute(key, value);
-          return true;
-        });
-
-    return log_record;
-  }
-};
-
-template <class ValueType>
-struct LogRecordSetterTrait
-{
-  static_assert(!std::is_same<nostd::unique_ptr<LogRecord>, ValueType>::value &&
-                    !std::is_same<std::unique_ptr<LogRecord>, ValueType>::value,
-                "unique_ptr<LogRecord> is not allowed, please use std::move()");
-
-  template <class ArgumentType,
-            nostd::enable_if_t<std::is_convertible<ArgumentType, nostd::string_view>::value ||
-                                   std::is_convertible<ArgumentType, common::AttributeValue>::value,
-                               void> * = nullptr>
-  inline static LogRecord *Set(LogRecord *log_record, ArgumentType &&arg) noexcept
-  {
-    log_record->SetBody(std::forward<ArgumentType>(arg));
-
-    return log_record;
-  }
-
-  template <class ArgumentType,
-            nostd::enable_if_t<std::is_base_of<common::KeyValueIterable, ArgumentType>::value, bool>
-                * = nullptr>
-  inline static LogRecord *Set(LogRecord *log_record, ArgumentType &&arg) noexcept
-  {
-    return LogRecordSetterTrait<common::KeyValueIterable>::Set(log_record,
-                                                               std::forward<ArgumentType>(arg));
-  }
-
-  template <class ArgumentType,
-            nostd::enable_if_t<common::detail::is_key_value_iterable<ArgumentType>::value, int> * =
-                nullptr>
-  inline static LogRecord *Set(LogRecord *log_record, ArgumentType &&arg) noexcept
-  {
-    for (auto &argv : arg)
-    {
-      log_record->SetAttribute(argv.first, argv.second);
-    }
-
-    return log_record;
-  }
-};
-
-template <class ValueType, class... ArgumentType>
-struct LogRecordHasType;
-
-template <class ValueType>
-struct LogRecordHasType<ValueType> : public std::false_type
-{};
-
-template <class ValueType, class TargetType, class... ArgumentType>
-struct LogRecordHasType<ValueType, TargetType, ArgumentType...>
-    : public std::conditional<std::is_same<ValueType, TargetType>::value,
-                              std::true_type,
-                              LogRecordHasType<ValueType, ArgumentType...>>::type
-{};
-
-}  // namespace detail
-
-}  // namespace logs
-OPENTELEMETRY_END_NAMESPACE
--- a/api/include/opentelemetry/logs/noop.h
+++ b/api/include/opentelemetry/logs/noop.h
@ -2,27 +2,34 @@
 // SPDX-License-Identifier: Apache-2.0

 #pragma once
+#ifdef ENABLE_LOGS_PREVIEW

 // Please refer to provider.h for documentation on how to obtain a Logger object.
 //
 // This file is part of the internal implementation of OpenTelemetry. Nothing in this file should be
 // used directly. Please refer to logger.h for documentation on these interfaces.

-#include "opentelemetry/logs/event_logger.h"
-#include "opentelemetry/logs/event_logger_provider.h"
-#include "opentelemetry/logs/logger.h"
-#include "opentelemetry/logs/logger_provider.h"
-#include "opentelemetry/nostd/shared_ptr.h"
-#include "opentelemetry/nostd/string_view.h"
-#include "opentelemetry/nostd/unique_ptr.h"
-#include "opentelemetry/version.h"
+#  include <memory>
+
+#  include "opentelemetry/common/attribute_value.h"
+#  include "opentelemetry/common/key_value_iterable.h"
+#  include "opentelemetry/common/timestamp.h"
+#  include "opentelemetry/context/runtime_context.h"
+#  include "opentelemetry/logs/logger.h"
+#  include "opentelemetry/logs/logger_provider.h"
+#  include "opentelemetry/logs/severity.h"
+#  include "opentelemetry/nostd/shared_ptr.h"
+#  include "opentelemetry/nostd/span.h"
+#  include "opentelemetry/nostd/string_view.h"
+#  include "opentelemetry/nostd/unique_ptr.h"
+#  include "opentelemetry/trace/span_id.h"
+#  include "opentelemetry/trace/trace_flags.h"
+#  include "opentelemetry/trace/trace_id.h"
+#  include "opentelemetry/version.h"
+
+#  include "opentelemetry/version.h"

 OPENTELEMETRY_BEGIN_NAMESPACE
-namespace common
-{
-class KeyValueIterable;
-}  // namespace common
-
 namespace logs
 {
 /**
@ -34,98 +41,44 @@ class NoopLogger final : public Logger
 public:
  const nostd::string_view GetName() noexcept override { return "noop logger"; }

-  nostd::unique_ptr<LogRecord> CreateLogRecord() noexcept override
-  {
-    /*
-     * Do not return memory shared between threads,
-     * a `new` + `delete` for each noop record can not be avoided,
-     * due to the semantic of unique_ptr.
-     */
-    return nostd::unique_ptr<LogRecord>(new NoopLogRecord());
-  }
-
-  using Logger::EmitLogRecord;
-
-  void EmitLogRecord(nostd::unique_ptr<LogRecord> &&) noexcept override {}
-
-private:
-  class NoopLogRecord : public LogRecord
-  {
-  public:
-    NoopLogRecord()           = default;
-    ~NoopLogRecord() override = default;
-
-    void SetTimestamp(common::SystemTimestamp /* timestamp */) noexcept override {}
-    void SetObservedTimestamp(common::SystemTimestamp /* timestamp */) noexcept override {}
-    void SetSeverity(logs::Severity /* severity */) noexcept override {}
-    void SetBody(const common::AttributeValue & /* message */) noexcept override {}
-    void SetAttribute(nostd::string_view /* key */,
-                      const common::AttributeValue & /* value */) noexcept override
-    {}
-    void SetEventId(int64_t /* id */, nostd::string_view /* name */) noexcept override {}
-    void SetTraceId(const trace::TraceId & /* trace_id */) noexcept override {}
-    void SetSpanId(const trace::SpanId & /* span_id */) noexcept override {}
-    void SetTraceFlags(const trace::TraceFlags & /* trace_flags */) noexcept override {}
-  };
+  void Log(Severity severity,
+           nostd::string_view name,
+           nostd::string_view body,
+           const common::KeyValueIterable &resource,
+           const common::KeyValueIterable &attributes,
+           trace::TraceId trace_id,
+           trace::SpanId span_id,
+           trace::TraceFlags trace_flags,
+           common::SystemTimestamp timestamp) noexcept override
+  {}
 };

 /**
 * No-op implementation of a LoggerProvider.
 */
-class NoopLoggerProvider final : public LoggerProvider
+class NoopLoggerProvider final : public opentelemetry::logs::LoggerProvider
 {
 public:
-  NoopLoggerProvider() : logger_{nostd::shared_ptr<NoopLogger>(new NoopLogger())} {}
+  NoopLoggerProvider()
+      : logger_{
+            nostd::shared_ptr<opentelemetry::logs::NoopLogger>(new opentelemetry::logs::NoopLogger)}
+  {}

-  nostd::shared_ptr<Logger> GetLogger(nostd::string_view /* logger_name */,
-                                      nostd::string_view /* library_name */,
-                                      nostd::string_view /* library_version */,
-                                      nostd::string_view /* schema_url */,
-                                      const common::KeyValueIterable & /* attributes */) override
+  nostd::shared_ptr<Logger> GetLogger(nostd::string_view logger_name,
+                                      nostd::string_view options) override
+  {
+    return logger_;
+  }
+
+  nostd::shared_ptr<Logger> GetLogger(nostd::string_view logger_name,
+                                      nostd::span<nostd::string_view> args) override
  {
    return logger_;
  }

 private:
-  nostd::shared_ptr<Logger> logger_;
+  nostd::shared_ptr<opentelemetry::logs::Logger> logger_;
 };
-
-#if OPENTELEMETRY_ABI_VERSION_NO < 2
-class NoopEventLogger final : public EventLogger
-{
-public:
-  NoopEventLogger() : logger_{nostd::shared_ptr<NoopLogger>(new NoopLogger())} {}
-
-  const nostd::string_view GetName() noexcept override { return "noop event logger"; }
-
-  nostd::shared_ptr<Logger> GetDelegateLogger() noexcept override { return logger_; }
-
-  void EmitEvent(nostd::string_view, nostd::unique_ptr<LogRecord> &&) noexcept override {}
-
-private:
-  nostd::shared_ptr<Logger> logger_;
-};
-
-/**
- * No-op implementation of a EventLoggerProvider.
- */
-class NoopEventLoggerProvider final : public EventLoggerProvider
-{
-public:
-  NoopEventLoggerProvider() : event_logger_{nostd::shared_ptr<EventLogger>(new NoopEventLogger())}
-  {}
-
-  nostd::shared_ptr<EventLogger> CreateEventLogger(
-      nostd::shared_ptr<Logger> /*delegate_logger*/,
-      nostd::string_view /*event_domain*/) noexcept override
-  {
-    return event_logger_;
-  }
-
-private:
-  nostd::shared_ptr<EventLogger> event_logger_;
-};
-#endif
-
 }  // namespace logs
 OPENTELEMETRY_END_NAMESPACE
+#endif
--- a/api/include/opentelemetry/logs/provider.h
+++ b/api/include/opentelemetry/logs/provider.h
@ -2,28 +2,22 @@
 // SPDX-License-Identifier: Apache-2.0

 #pragma once
+#ifdef ENABLE_LOGS_PREVIEW

-#include <mutex>
+#  include <mutex>

-#include "opentelemetry/common/macros.h"
-#include "opentelemetry/common/spin_lock_mutex.h"
-#include "opentelemetry/logs/noop.h"
-#include "opentelemetry/nostd/shared_ptr.h"
-#include "opentelemetry/version.h"
+#  include "opentelemetry/common/spin_lock_mutex.h"
+#  include "opentelemetry/logs/logger_provider.h"
+#  include "opentelemetry/logs/noop.h"
+#  include "opentelemetry/nostd/shared_ptr.h"

 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace logs
 {
-
-#if OPENTELEMETRY_ABI_VERSION_NO < 2
-class EventLoggerProvider;
-#endif
-class LoggerProvider;
-
 /**
 * Stores the singleton global LoggerProvider.
 */
-class OPENTELEMETRY_EXPORT Provider
+class Provider
 {
 public:
  /**
@ -41,55 +35,20 @@ public:
  /**
   * Changes the singleton LoggerProvider.
   */
-  static void SetLoggerProvider(const nostd::shared_ptr<LoggerProvider> &tp) noexcept
+  static void SetLoggerProvider(nostd::shared_ptr<LoggerProvider> tp) noexcept
  {
    std::lock_guard<common::SpinLockMutex> guard(GetLock());
    GetProvider() = tp;
  }

-#if OPENTELEMETRY_ABI_VERSION_NO < 2
-  /**
-   * Returns the singleton EventLoggerProvider.
-   *
-   * By default, a no-op EventLoggerProvider is returned. This will never return a
-   * nullptr EventLoggerProvider.
-   */
-  OPENTELEMETRY_DEPRECATED static nostd::shared_ptr<EventLoggerProvider>
-  GetEventLoggerProvider() noexcept
-  {
-    std::lock_guard<common::SpinLockMutex> guard(GetLock());
-    return nostd::shared_ptr<EventLoggerProvider>(GetEventProvider());
-  }
-
-  /**
-   * Changes the singleton EventLoggerProvider.
-   */
-  OPENTELEMETRY_DEPRECATED static void SetEventLoggerProvider(
-      const nostd::shared_ptr<EventLoggerProvider> &tp) noexcept
-  {
-    std::lock_guard<common::SpinLockMutex> guard(GetLock());
-    GetEventProvider() = tp;
-  }
-#endif
-
 private:
-  OPENTELEMETRY_API_SINGLETON static nostd::shared_ptr<LoggerProvider> &GetProvider() noexcept
+  static nostd::shared_ptr<LoggerProvider> &GetProvider() noexcept
  {
    static nostd::shared_ptr<LoggerProvider> provider(new NoopLoggerProvider);
    return provider;
  }

-#if OPENTELEMETRY_ABI_VERSION_NO < 2
-  OPENTELEMETRY_DEPRECATED
-  OPENTELEMETRY_API_SINGLETON static nostd::shared_ptr<EventLoggerProvider> &
-  GetEventProvider() noexcept
-  {
-    static nostd::shared_ptr<EventLoggerProvider> provider(new NoopEventLoggerProvider);
-    return provider;
-  }
-#endif
-
-  OPENTELEMETRY_API_SINGLETON static common::SpinLockMutex &GetLock() noexcept
+  static common::SpinLockMutex &GetLock() noexcept
  {
    static common::SpinLockMutex lock;
    return lock;
@ -98,3 +57,4 @@ private:

 }  // namespace logs
 OPENTELEMETRY_END_NAMESPACE
+#endif
--- a/api/include/opentelemetry/logs/severity.h
+++ b/api/include/opentelemetry/logs/severity.h
@ -2,11 +2,9 @@
 // SPDX-License-Identifier: Apache-2.0

 #pragma once
+#ifdef ENABLE_LOGS_PREVIEW

-#include <cstdint>
-
-#include "opentelemetry/nostd/string_view.h"
-#include "opentelemetry/version.h"
+#  include "opentelemetry/version.h"

 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace logs
@ -15,41 +13,36 @@ namespace logs
 /**
 * Severity Levels assigned to log events, based on Log Data Model,
 * with the addition of kInvalid (mapped to a severity number of 0).
- *
- * See
- * https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/logs/data-model.md#field-severitynumber
 */
 enum class Severity : uint8_t
 {
-  kInvalid = 0,
-  kTrace   = 1,
-  kTrace2  = 2,
-  kTrace3  = 3,
-  kTrace4  = 4,
-  kDebug   = 5,
-  kDebug2  = 6,
-  kDebug3  = 7,
-  kDebug4  = 8,
-  kInfo    = 9,
-  kInfo2   = 10,
-  kInfo3   = 11,
-  kInfo4   = 12,
-  kWarn    = 13,
-  kWarn2   = 14,
-  kWarn3   = 15,
-  kWarn4   = 16,
-  kError   = 17,
-  kError2  = 18,
-  kError3  = 19,
-  kError4  = 20,
-  kFatal   = 21,
-  kFatal2  = 22,
-  kFatal3  = 23,
-  kFatal4  = 24
+  kInvalid,
+  kTrace,
+  kTrace2,
+  kTrace3,
+  kTrace4,
+  kDebug,
+  kDebug2,
+  kDebug3,
+  kDebug4,
+  kInfo,
+  kInfo2,
+  kInfo3,
+  kInfo4,
+  kWarn,
+  kWarn2,
+  kWarn3,
+  kWarn4,
+  kError,
+  kError2,
+  kError3,
+  kError4,
+  kFatal,
+  kFatal2,
+  kFatal3,
+  kFatal4
 };

-const uint8_t kMaxSeverity = 255;
-
 /**
 * Mapping of the severity enum above, to a severity text string (in all caps).
 * This severity text can be printed out by exporters. Capital letters follow the
@ -58,10 +51,11 @@ const uint8_t kMaxSeverity = 255;
 * Included to follow the specification's recommendation to print both
 * severity number and text in each log record.
 */
-const nostd::string_view SeverityNumToText[25] = {
+const opentelemetry::nostd::string_view SeverityNumToText[25] = {
    "INVALID", "TRACE",  "TRACE2", "TRACE3", "TRACE4", "DEBUG",  "DEBUG2", "DEBUG3", "DEBUG4",
    "INFO",    "INFO2",  "INFO3",  "INFO4",  "WARN",   "WARN2",  "WARN3",  "WARN4",  "ERROR",
    "ERROR2",  "ERROR3", "ERROR4", "FATAL",  "FATAL2", "FATAL3", "FATAL4"};

 }  // namespace logs
 OPENTELEMETRY_END_NAMESPACE
+#endif
--- a/api/include/opentelemetry/metrics/async_instruments.h
+++ b/api/include/opentelemetry/metrics/async_instruments.h
@ -2,32 +2,28 @@
 // SPDX-License-Identifier: Apache-2.0

 #pragma once
+#ifndef ENABLE_METRICS_PREVIEW

-#include "opentelemetry/metrics/observer_result.h"
-#include "opentelemetry/version.h"
+#  include "observer_result.h"

 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace metrics
 {
+class AsynchronousInstrument
+{};

-using ObservableCallbackPtr = void (*)(ObserverResult, void *);
+template <class T>
+class ObservableCounter : public AsynchronousInstrument
+{};

-class ObservableInstrument
-{
-public:
-  ObservableInstrument()          = default;
-  virtual ~ObservableInstrument() = default;
+template <class T>
+class ObservableGauge : public AsynchronousInstrument
+{};

-  /**
-   * Sets up a function that will be called whenever a metric collection is initiated.
-   */
-  virtual void AddCallback(ObservableCallbackPtr, void *state) noexcept = 0;
-
-  /**
-   * Remove a function that was configured to be called whenever a metric collection is initiated.
-   */
-  virtual void RemoveCallback(ObservableCallbackPtr, void *state) noexcept = 0;
-};
+template <class T>
+class ObservableUpDownCounter : public AsynchronousInstrument
+{};

 }  // namespace metrics
 OPENTELEMETRY_END_NAMESPACE
+#endif
--- a/api/include/opentelemetry/metrics/meter.h
+++ b/api/include/opentelemetry/metrics/meter.h
@ -2,30 +2,18 @@
 // SPDX-License-Identifier: Apache-2.0

 #pragma once
+#ifndef ENABLE_METRICS_PREVIEW

-#include "opentelemetry/nostd/shared_ptr.h"
-#include "opentelemetry/nostd/string_view.h"
-#include "opentelemetry/nostd/unique_ptr.h"
-#include "opentelemetry/version.h"
+#  include "opentelemetry/metrics/async_instruments.h"
+#  include "opentelemetry/metrics/sync_instruments.h"
+#  include "opentelemetry/nostd/shared_ptr.h"
+#  include "opentelemetry/nostd/span.h"
+#  include "opentelemetry/nostd/string_view.h"
+#  include "opentelemetry/version.h"

 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace metrics
 {
-
-template <typename T>
-class Counter;
-
-template <typename T>
-class Histogram;
-
-template <typename T>
-class UpDownCounter;
-
-template <typename T>
-class Gauge;
-
-class ObservableInstrument;
-
 /**
 * Handles instrument creation and provides a facility for batch recording.
 *
@ -40,7 +28,7 @@ public:
  virtual ~Meter() = default;

  /**
-   * Creates a Counter with the passed characteristics and returns a unique_ptr to that Counter.
+   * Creates a Counter with the passed characteristics and returns a shared_ptr to that Counter.
   *
   * @param name the name of the new Counter.
   * @param description a brief description of what the Counter is used for.
@ -48,93 +36,80 @@ public:
   * @return a shared pointer to the created Counter.
   */

-  virtual nostd::unique_ptr<Counter<uint64_t>> CreateUInt64Counter(
+  virtual nostd::shared_ptr<Counter<long>> CreateLongCounter(
      nostd::string_view name,
      nostd::string_view description = "",
      nostd::string_view unit        = "") noexcept = 0;

-  virtual nostd::unique_ptr<Counter<double>> CreateDoubleCounter(
+  virtual nostd::shared_ptr<Counter<double>> CreateDoubleCounter(
      nostd::string_view name,
      nostd::string_view description = "",
      nostd::string_view unit        = "") noexcept = 0;

  /**
-   * Creates a Asynchronous (Observable) counter with the passed characteristics and returns a
+   * Creates a Asynchronouse (Observable) counter with the passed characteristics and returns a
   * shared_ptr to that Observable Counter
   *
   * @param name the name of the new Observable Counter.
   * @param description a brief description of what the Observable Counter is used for.
   * @param unit the unit of metric values following https://unitsofmeasure.org/ucum.html.
+   * @param callback the function to be observed by the instrument.
+   * @return a shared pointer to the created Observable Counter.
   */
-  virtual nostd::shared_ptr<ObservableInstrument> CreateInt64ObservableCounter(
+  virtual nostd::shared_ptr<ObservableCounter<long>> CreateLongObservableCounter(
      nostd::string_view name,
+      void (*callback)(ObserverResult<long> &),
      nostd::string_view description = "",
      nostd::string_view unit        = "") noexcept = 0;

-  virtual nostd::shared_ptr<ObservableInstrument> CreateDoubleObservableCounter(
+  virtual nostd::shared_ptr<ObservableCounter<double>> CreateDoubleObservableCounter(
      nostd::string_view name,
+      void (*callback)(ObserverResult<double> &),
      nostd::string_view description = "",
      nostd::string_view unit        = "") noexcept = 0;

  /**
-   * Creates a Histogram with the passed characteristics and returns a unique_ptr to that Histogram.
+   * Creates a Histogram with the passed characteristics and returns a shared_ptr to that Histogram.
   *
   * @param name the name of the new Histogram.
   * @param description a brief description of what the Histogram is used for.
   * @param unit the unit of metric values following https://unitsofmeasure.org/ucum.html.
   * @return a shared pointer to the created Histogram.
   */
-  virtual nostd::unique_ptr<Histogram<uint64_t>> CreateUInt64Histogram(
+  virtual nostd::shared_ptr<Histogram<long>> CreateLongHistogram(
      nostd::string_view name,
      nostd::string_view description = "",
      nostd::string_view unit        = "") noexcept = 0;

-  virtual nostd::unique_ptr<Histogram<double>> CreateDoubleHistogram(
+  virtual nostd::shared_ptr<Histogram<double>> CreateDoubleHistogram(
      nostd::string_view name,
      nostd::string_view description = "",
      nostd::string_view unit        = "") noexcept = 0;

-#if OPENTELEMETRY_ABI_VERSION_NO >= 2
-  /**
-   * Creates a Gauge with the passed characteristics and returns a unique_ptr to that Gauge.
-   *
-   * @param name the name of the new Gauge.
-   * @param description a brief description of what the Gauge is used for.
-   * @param unit the unit of metric values following https://unitsofmeasure.org/ucum.html.
-   * @return a unique pointer to the created Gauge.
-   */
-
-  virtual nostd::unique_ptr<Gauge<int64_t>> CreateInt64Gauge(
-      nostd::string_view name,
-      nostd::string_view description = "",
-      nostd::string_view unit        = "") noexcept = 0;
-
-  virtual nostd::unique_ptr<Gauge<double>> CreateDoubleGauge(
-      nostd::string_view name,
-      nostd::string_view description = "",
-      nostd::string_view unit        = "") noexcept = 0;
-#endif
-
  /**
-   * Creates a Asynchronous (Observable) Gauge with the passed characteristics and returns a
-   * shared_ptr to that Observable Gauge
+   * Creates a Asynchronouse (Observable) Gauge with the passed characteristics and returns a
+   * shared_ptr to that Observable Counter
   *
   * @param name the name of the new Observable Gauge.
   * @param description a brief description of what the Observable Gauge is used for.
   * @param unit the unit of metric values following https://unitsofmeasure.org/ucum.html.
+   * @param callback the function to be observed by the instrument.
+   * @return a shared pointer to the created Observable Gauge.
   */
-  virtual nostd::shared_ptr<ObservableInstrument> CreateInt64ObservableGauge(
+  virtual nostd::shared_ptr<ObservableGauge<long>> CreateLongObservableGauge(
      nostd::string_view name,
+      void (*callback)(ObserverResult<long> &),
      nostd::string_view description = "",
      nostd::string_view unit        = "") noexcept = 0;

-  virtual nostd::shared_ptr<ObservableInstrument> CreateDoubleObservableGauge(
+  virtual nostd::shared_ptr<ObservableGauge<double>> CreateDoubleObservableGauge(
      nostd::string_view name,
+      void (*callback)(ObserverResult<double> &),
      nostd::string_view description = "",
      nostd::string_view unit        = "") noexcept = 0;

  /**
-   * Creates an UpDownCounter with the passed characteristics and returns a unique_ptr to that
+   * Creates an UpDownCounter with the passed characteristics and returns a shared_ptr to that
   * UpDownCounter.
   *
   * @param name the name of the new UpDownCounter.
@ -142,33 +117,38 @@ public:
   * @param unit the unit of metric values following https://unitsofmeasure.org/ucum.html.
   * @return a shared pointer to the created UpDownCounter.
   */
-  virtual nostd::unique_ptr<UpDownCounter<int64_t>> CreateInt64UpDownCounter(
+  virtual nostd::shared_ptr<UpDownCounter<long>> CreateLongUpDownCounter(
      nostd::string_view name,
      nostd::string_view description = "",
      nostd::string_view unit        = "") noexcept = 0;

-  virtual nostd::unique_ptr<UpDownCounter<double>> CreateDoubleUpDownCounter(
+  virtual nostd::shared_ptr<UpDownCounter<double>> CreateDoubleUpDownCounter(
      nostd::string_view name,
      nostd::string_view description = "",
      nostd::string_view unit        = "") noexcept = 0;

  /**
-   * Creates a Asynchronous (Observable) UpDownCounter with the passed characteristics and returns
+   * Creates a Asynchronouse (Observable) UpDownCounter with the passed characteristics and returns
   * a shared_ptr to that Observable UpDownCounter
   *
   * @param name the name of the new Observable UpDownCounter.
   * @param description a brief description of what the Observable UpDownCounter is used for.
   * @param unit the unit of metric values following https://unitsofmeasure.org/ucum.html.
+   * @param callback the function to be observed by the instrument.
+   * @return a shared pointer to the created Observable UpDownCounter.
   */
-  virtual nostd::shared_ptr<ObservableInstrument> CreateInt64ObservableUpDownCounter(
+  virtual nostd::shared_ptr<ObservableUpDownCounter<long>> CreateLongObservableUpDownCounter(
      nostd::string_view name,
+      void (*callback)(ObserverResult<long> &),
      nostd::string_view description = "",
      nostd::string_view unit        = "") noexcept = 0;

-  virtual nostd::shared_ptr<ObservableInstrument> CreateDoubleObservableUpDownCounter(
+  virtual nostd::shared_ptr<ObservableUpDownCounter<double>> CreateDoubleObservableUpDownCounter(
      nostd::string_view name,
+      void (*callback)(ObserverResult<double> &),
      nostd::string_view description = "",
      nostd::string_view unit        = "") noexcept = 0;
 };
 }  // namespace metrics
 OPENTELEMETRY_END_NAMESPACE
+#endif
--- a/api/include/opentelemetry/metrics/meter_provider.h
+++ b/api/include/opentelemetry/metrics/meter_provider.h
@ -2,20 +2,15 @@
 // SPDX-License-Identifier: Apache-2.0

 #pragma once
+#ifndef ENABLE_METRICS_PREVIEW

-#include "opentelemetry/common/key_value_iterable.h"
-#include "opentelemetry/common/key_value_iterable_view.h"
-#include "opentelemetry/nostd/shared_ptr.h"
-#include "opentelemetry/nostd/string_view.h"
-#include "opentelemetry/nostd/type_traits.h"
-#include "opentelemetry/version.h"
+#  include "opentelemetry/metrics/meter.h"
+#  include "opentelemetry/nostd/shared_ptr.h"
+#  include "opentelemetry/nostd/string_view.h"

 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace metrics
 {
-
-class Meter;
-
 /**
 * Creates new Meter instances.
 */
@ -23,126 +18,16 @@ class MeterProvider
 {
 public:
  virtual ~MeterProvider() = default;
-
-#if OPENTELEMETRY_ABI_VERSION_NO >= 2
-
  /**
-   * Gets or creates a named Meter instance (ABI).
+   * Gets or creates a named Meter instance.
   *
-   * @since ABI_VERSION 2
-   *
-   * @param[in] name Meter instrumentation scope
-   * @param[in] version Instrumentation scope version
-   * @param[in] schema_url Instrumentation scope schema URL
-   * @param[in] attributes Instrumentation scope attributes (optional, may be nullptr)
+   * Optionally a version can be passed to create a named and versioned Meter
+   * instance.
   */
-  virtual nostd::shared_ptr<Meter> GetMeter(
-      nostd::string_view name,
-      nostd::string_view version,
-      nostd::string_view schema_url,
-      const common::KeyValueIterable *attributes) noexcept = 0;
-
-  /**
-   * Gets or creates a named Meter instance (API helper).
-   *
-   * @since ABI_VERSION 2
-   *
-   * @param[in] name Meter instrumentation scope
-   * @param[in] version Instrumentation scope version, optional
-   * @param[in] schema_url Instrumentation scope schema URL, optional
-   */
-  nostd::shared_ptr<Meter> GetMeter(nostd::string_view name,
-                                    nostd::string_view version    = "",
-                                    nostd::string_view schema_url = "")
-  {
-    return GetMeter(name, version, schema_url, nullptr);
-  }
-
-  /**
-   * Gets or creates a named Meter instance (API helper).
-   *
-   * @since ABI_VERSION 2
-   *
-   * @param[in] name Meter instrumentation scope
-   * @param[in] version Instrumentation scope version
-   * @param[in] schema_url Instrumentation scope schema URL
-   * @param[in] attributes Instrumentation scope attributes
-   */
-  nostd::shared_ptr<Meter> GetMeter(
-      nostd::string_view name,
-      nostd::string_view version,
-      nostd::string_view schema_url,
-      std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>> attributes)
-  {
-    /* Build a container from std::initializer_list. */
-    nostd::span<const std::pair<nostd::string_view, common::AttributeValue>> attributes_span{
-        attributes.begin(), attributes.end()};
-
-    /* Build a view on the container. */
-    common::KeyValueIterableView<
-        nostd::span<const std::pair<nostd::string_view, common::AttributeValue>>>
-        iterable_attributes{attributes_span};
-
-    /* Add attributes using the view. */
-    return GetMeter(name, version, schema_url, &iterable_attributes);
-  }
-
-  /**
-   * Gets or creates a named Meter instance (API helper).
-   *
-   * @since ABI_VERSION 2
-   *
-   * @param[in] name Meter instrumentation scope
-   * @param[in] version Instrumentation scope version
-   * @param[in] schema_url Instrumentation scope schema URL
-   * @param[in] attributes Instrumentation scope attributes container
-   */
-  template <class T,
-            nostd::enable_if_t<common::detail::is_key_value_iterable<T>::value> * = nullptr>
-  nostd::shared_ptr<Meter> GetMeter(nostd::string_view name,
-                                    nostd::string_view version,
-                                    nostd::string_view schema_url,
-                                    const T &attributes)
-  {
-    /* Build a view on the container. */
-    common::KeyValueIterableView<T> iterable_attributes(attributes);
-
-    /* Add attributes using the view. */
-    return GetMeter(name, version, schema_url, &iterable_attributes);
-  }
-
-#else
-  /**
-   * Gets or creates a named Meter instance (ABI)
-   *
-   * @since ABI_VERSION 1
-   *
-   * @param[in] name Meter instrumentation scope
-   * @param[in] version Instrumentation scope version, optional
-   * @param[in] schema_url Instrumentation scope schema URL, optional
-   */
-  virtual nostd::shared_ptr<Meter> GetMeter(nostd::string_view name,
-                                            nostd::string_view version    = "",
-                                            nostd::string_view schema_url = "") noexcept = 0;
-#endif
-
-#if OPENTELEMETRY_ABI_VERSION_NO >= 2
-  /**
-   * Remove a named Meter instance (ABI).
-   *
-   * This API is experimental, see
-   * https://github.com/open-telemetry/opentelemetry-specification/issues/2232
-   *
-   * @since ABI_VERSION 2
-   *
-   * @param[in] name Meter instrumentation scope
-   * @param[in] version Instrumentation scope version, optional
-   * @param[in] schema_url Instrumentation scope schema URL, optional
-   */
-  virtual void RemoveMeter(nostd::string_view name,
-                           nostd::string_view version    = "",
-                           nostd::string_view schema_url = "") noexcept = 0;
-#endif
+  virtual nostd::shared_ptr<Meter> GetMeter(nostd::string_view library_name,
+                                            nostd::string_view library_version = "",
+                                            nostd::string_view schema_url      = "") noexcept = 0;
 };
 }  // namespace metrics
 OPENTELEMETRY_END_NAMESPACE
+#endif
--- a/api/include/opentelemetry/metrics/noop.h
+++ b/api/include/opentelemetry/metrics/noop.h
@ -2,13 +2,14 @@
 // SPDX-License-Identifier: Apache-2.0

 #pragma once
+#ifndef ENABLE_METRICS_PREVIEW

-#include "opentelemetry/metrics/async_instruments.h"
-#include "opentelemetry/metrics/meter.h"
-#include "opentelemetry/metrics/meter_provider.h"
-#include "opentelemetry/metrics/observer_result.h"
-#include "opentelemetry/metrics/sync_instruments.h"
-#include "opentelemetry/version.h"
+#  include "opentelemetry/metrics/async_instruments.h"
+#  include "opentelemetry/metrics/meter.h"
+#  include "opentelemetry/metrics/meter_provider.h"
+#  include "opentelemetry/metrics/observer_result.h"
+#  include "opentelemetry/metrics/sync_instruments.h"
+#  include "opentelemetry/version.h"

 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace metrics
@ -18,89 +19,88 @@ template <class T>
 class NoopCounter : public Counter<T>
 {
 public:
-  NoopCounter(nostd::string_view /* name */,
-              nostd::string_view /* description */,
-              nostd::string_view /* unit */) noexcept
-  {}
-  void Add(T /* value */) noexcept override {}
-  void Add(T /* value */, const context::Context & /* context */) noexcept override {}
-  void Add(T /* value */, const common::KeyValueIterable & /* attributes */) noexcept override {}
-  void Add(T /* value */,
-           const common::KeyValueIterable & /* attributes */,
-           const context::Context & /* context */) noexcept override
+  NoopCounter(nostd::string_view name,
+              nostd::string_view description,
+              nostd::string_view unit) noexcept
  {}
+  void Add(T value) noexcept override {}
+  void Add(T value, const common::KeyValueIterable &attributes) noexcept override {}
 };

 template <class T>
 class NoopHistogram : public Histogram<T>
 {
 public:
-  NoopHistogram(nostd::string_view /* name */,
-                nostd::string_view /* description */,
-                nostd::string_view /* unit */) noexcept
+  NoopHistogram(nostd::string_view name,
+                nostd::string_view description,
+                nostd::string_view unit) noexcept
  {}
-  void Record(T /* value */, const context::Context & /* context */) noexcept override {}
-  void Record(T /* value */,
-              const common::KeyValueIterable & /* attributes */,
-              const context::Context & /* context */) noexcept override
-  {}
-#if OPENTELEMETRY_ABI_VERSION_NO >= 2
-  void Record(T /*value*/,
-              const opentelemetry::common::KeyValueIterable & /*attributes*/) noexcept override
-  {}
-
-  void Record(T /*value*/) noexcept override {}
-#endif
+  void Record(T value) noexcept override {}
+  void Record(T value, const common::KeyValueIterable &attributes) noexcept override {}
 };

 template <class T>
 class NoopUpDownCounter : public UpDownCounter<T>
 {
 public:
-  NoopUpDownCounter(nostd::string_view /* name */,
-                    nostd::string_view /* description */,
-                    nostd::string_view /* unit */) noexcept
-  {}
-  ~NoopUpDownCounter() override = default;
-  void Add(T /* value */) noexcept override {}
-  void Add(T /* value */, const context::Context & /* context */) noexcept override {}
-  void Add(T /* value */, const common::KeyValueIterable & /* attributes */) noexcept override {}
-  void Add(T /* value */,
-           const common::KeyValueIterable & /* attributes */,
-           const context::Context & /* context */) noexcept override
+  NoopUpDownCounter(nostd::string_view name,
+                    nostd::string_view description,
+                    nostd::string_view unit) noexcept
  {}
+  void Add(T value) noexcept override {}
+  void Add(T value, const common::KeyValueIterable &attributes) noexcept override {}
 };

-#if OPENTELEMETRY_ABI_VERSION_NO >= 2
 template <class T>
-class NoopGauge : public Gauge<T>
+class NoopObservableCounter : public ObservableCounter<T>
 {
 public:
-  NoopGauge(nostd::string_view /* name */,
-            nostd::string_view /* description */,
-            nostd::string_view /* unit */) noexcept
+  NoopObservableCounter(nostd::string_view name,
+                        void (*callback)(ObserverResult<T> &),
+                        nostd::string_view description,
+                        nostd::string_view unit) noexcept
  {}
-  ~NoopGauge() override = default;
-  void Record(T /* value */) noexcept override {}
-  void Record(T /* value */, const context::Context & /* context */) noexcept override {}
-  void Record(T /* value */, const common::KeyValueIterable & /* attributes */) noexcept override {}
-  void Record(T /* value */,
-              const common::KeyValueIterable & /* attributes */,
-              const context::Context & /* context */) noexcept override
+
+  NoopObservableCounter(nostd::string_view name,
+                        void (*callback)(ObserverResult<T> &, const common::KeyValueIterable &),
+                        nostd::string_view description,
+                        nostd::string_view unit) noexcept
  {}
 };
-#endif

-class NoopObservableInstrument : public ObservableInstrument
+template <class T>
+class NoopObservableGauge : public ObservableGauge<T>
 {
 public:
-  NoopObservableInstrument(nostd::string_view /* name */,
-                           nostd::string_view /* description */,
-                           nostd::string_view /* unit */) noexcept
+  NoopObservableGauge(nostd::string_view name,
+                      void (*callback)(ObserverResult<T> &),
+                      nostd::string_view description,
+                      nostd::string_view unit) noexcept
  {}

-  void AddCallback(ObservableCallbackPtr, void * /* state */) noexcept override {}
-  void RemoveCallback(ObservableCallbackPtr, void * /* state */) noexcept override {}
+  NoopObservableGauge(nostd::string_view name,
+                      void (*callback)(ObserverResult<T> &, const common::KeyValueIterable &),
+                      nostd::string_view description,
+                      nostd::string_view unit) noexcept
+  {}
+};
+
+template <class T>
+class NoopObservableUpDownCounter : public ObservableUpDownCounter<T>
+{
+public:
+  NoopObservableUpDownCounter(nostd::string_view name,
+                              void (*callback)(ObserverResult<T> &),
+                              nostd::string_view description,
+                              nostd::string_view unit) noexcept
+  {}
+
+  NoopObservableUpDownCounter(nostd::string_view name,
+                              void (*callback)(ObserverResult<T> &,
+                                               const common::KeyValueIterable &),
+                              nostd::string_view description,
+                              nostd::string_view unit) noexcept
+  {}
 };

 /**
@ -109,125 +109,113 @@ public:
 class NoopMeter final : public Meter
 {
 public:
-  nostd::unique_ptr<Counter<uint64_t>> CreateUInt64Counter(
-      nostd::string_view name,
-      nostd::string_view description = "",
-      nostd::string_view unit        = "") noexcept override
-  {
-    return nostd::unique_ptr<Counter<uint64_t>>{new NoopCounter<uint64_t>(name, description, unit)};
-  }
-
-  nostd::unique_ptr<Counter<double>> CreateDoubleCounter(
-      nostd::string_view name,
-      nostd::string_view description = "",
-      nostd::string_view unit        = "") noexcept override
-  {
-    return nostd::unique_ptr<Counter<double>>{new NoopCounter<double>(name, description, unit)};
-  }
-
-  nostd::shared_ptr<ObservableInstrument> CreateInt64ObservableCounter(
-      nostd::string_view name,
-      nostd::string_view description = "",
-      nostd::string_view unit        = "") noexcept override
-  {
-    return nostd::shared_ptr<ObservableInstrument>(
-        new NoopObservableInstrument(name, description, unit));
-  }
-
-  nostd::shared_ptr<ObservableInstrument> CreateDoubleObservableCounter(
-      nostd::string_view name,
-      nostd::string_view description = "",
-      nostd::string_view unit        = "") noexcept override
-  {
-    return nostd::shared_ptr<ObservableInstrument>(
-        new NoopObservableInstrument(name, description, unit));
-  }
-
-  nostd::unique_ptr<Histogram<uint64_t>> CreateUInt64Histogram(
-      nostd::string_view name,
-      nostd::string_view description = "",
-      nostd::string_view unit        = "") noexcept override
-  {
-    return nostd::unique_ptr<Histogram<uint64_t>>{
-        new NoopHistogram<uint64_t>(name, description, unit)};
-  }
-
-  nostd::unique_ptr<Histogram<double>> CreateDoubleHistogram(
-      nostd::string_view name,
-      nostd::string_view description = "",
-      nostd::string_view unit        = "") noexcept override
-  {
-    return nostd::unique_ptr<Histogram<double>>{new NoopHistogram<double>(name, description, unit)};
-  }
-
-#if OPENTELEMETRY_ABI_VERSION_NO >= 2
-  nostd::unique_ptr<Gauge<int64_t>> CreateInt64Gauge(nostd::string_view name,
+  nostd::shared_ptr<Counter<long>> CreateLongCounter(nostd::string_view name,
                                                     nostd::string_view description = "",
                                                     nostd::string_view unit = "") noexcept override
  {
-    return nostd::unique_ptr<Gauge<int64_t>>{new NoopGauge<int64_t>(name, description, unit)};
+    return nostd::shared_ptr<Counter<long>>{new NoopCounter<long>(name, description, unit)};
  }

-  nostd::unique_ptr<Gauge<double>> CreateDoubleGauge(nostd::string_view name,
-                                                     nostd::string_view description = "",
-                                                     nostd::string_view unit = "") noexcept override
-  {
-    return nostd::unique_ptr<Gauge<double>>{new NoopGauge<double>(name, description, unit)};
-  }
-#endif
-
-  nostd::shared_ptr<ObservableInstrument> CreateInt64ObservableGauge(
+  nostd::shared_ptr<Counter<double>> CreateDoubleCounter(
      nostd::string_view name,
      nostd::string_view description = "",
      nostd::string_view unit        = "") noexcept override
  {
-    return nostd::shared_ptr<ObservableInstrument>(
-        new NoopObservableInstrument(name, description, unit));
+    return nostd::shared_ptr<Counter<double>>{new NoopCounter<double>(name, description, unit)};
  }

-  nostd::shared_ptr<ObservableInstrument> CreateDoubleObservableGauge(
+  nostd::shared_ptr<ObservableCounter<long>> CreateLongObservableCounter(
+      nostd::string_view name,
+      void (*callback)(ObserverResult<long> &),
+      nostd::string_view description = "",
+      nostd::string_view unit        = "") noexcept override
+  {
+    return nostd::shared_ptr<ObservableCounter<long>>{
+        new NoopObservableCounter<long>(name, callback, description, unit)};
+  }
+
+  nostd::shared_ptr<ObservableCounter<double>> CreateDoubleObservableCounter(
+      nostd::string_view name,
+      void (*callback)(ObserverResult<double> &),
+      nostd::string_view description = "",
+      nostd::string_view unit        = "") noexcept override
+  {
+    return nostd::shared_ptr<ObservableCounter<double>>{
+        new NoopObservableCounter<double>(name, callback, description, unit)};
+  }
+
+  nostd::shared_ptr<Histogram<long>> CreateLongHistogram(
      nostd::string_view name,
      nostd::string_view description = "",
      nostd::string_view unit        = "") noexcept override
  {
-    return nostd::shared_ptr<ObservableInstrument>(
-        new NoopObservableInstrument(name, description, unit));
+    return nostd::shared_ptr<Histogram<long>>{new NoopHistogram<long>(name, description, unit)};
  }

-  nostd::unique_ptr<UpDownCounter<int64_t>> CreateInt64UpDownCounter(
+  nostd::shared_ptr<Histogram<double>> CreateDoubleHistogram(
      nostd::string_view name,
      nostd::string_view description = "",
      nostd::string_view unit        = "") noexcept override
  {
-    return nostd::unique_ptr<UpDownCounter<int64_t>>{
-        new NoopUpDownCounter<int64_t>(name, description, unit)};
+    return nostd::shared_ptr<Histogram<double>>{new NoopHistogram<double>(name, description, unit)};
  }

-  nostd::unique_ptr<UpDownCounter<double>> CreateDoubleUpDownCounter(
+  nostd::shared_ptr<ObservableGauge<long>> CreateLongObservableGauge(
+      nostd::string_view name,
+      void (*callback)(ObserverResult<long> &),
+      nostd::string_view description = "",
+      nostd::string_view unit        = "") noexcept override
+  {
+    return nostd::shared_ptr<ObservableGauge<long>>{
+        new NoopObservableGauge<long>(name, callback, description, unit)};
+  }
+
+  nostd::shared_ptr<ObservableGauge<double>> CreateDoubleObservableGauge(
+      nostd::string_view name,
+      void (*callback)(ObserverResult<double> &),
+      nostd::string_view description = "",
+      nostd::string_view unit        = "") noexcept override
+  {
+    return nostd::shared_ptr<ObservableGauge<double>>{
+        new NoopObservableGauge<double>(name, callback, description, unit)};
+  }
+
+  nostd::shared_ptr<UpDownCounter<long>> CreateLongUpDownCounter(
      nostd::string_view name,
      nostd::string_view description = "",
      nostd::string_view unit        = "") noexcept override
  {
-    return nostd::unique_ptr<UpDownCounter<double>>{
+    return nostd::shared_ptr<UpDownCounter<long>>{
+        new NoopUpDownCounter<long>(name, description, unit)};
+  }
+
+  nostd::shared_ptr<UpDownCounter<double>> CreateDoubleUpDownCounter(
+      nostd::string_view name,
+      nostd::string_view description = "",
+      nostd::string_view unit        = "") noexcept override
+  {
+    return nostd::shared_ptr<UpDownCounter<double>>{
        new NoopUpDownCounter<double>(name, description, unit)};
  }

-  nostd::shared_ptr<ObservableInstrument> CreateInt64ObservableUpDownCounter(
+  nostd::shared_ptr<ObservableUpDownCounter<long>> CreateLongObservableUpDownCounter(
      nostd::string_view name,
+      void (*callback)(ObserverResult<long> &),
      nostd::string_view description = "",
      nostd::string_view unit        = "") noexcept override
  {
-    return nostd::shared_ptr<ObservableInstrument>(
-        new NoopObservableInstrument(name, description, unit));
+    return nostd::shared_ptr<ObservableUpDownCounter<long>>{
+        new NoopObservableUpDownCounter<long>(name, callback, description, unit)};
  }

-  nostd::shared_ptr<ObservableInstrument> CreateDoubleObservableUpDownCounter(
+  nostd::shared_ptr<ObservableUpDownCounter<double>> CreateDoubleObservableUpDownCounter(
      nostd::string_view name,
+      void (*callback)(ObserverResult<double> &),
      nostd::string_view description = "",
      nostd::string_view unit        = "") noexcept override
  {
-    return nostd::shared_ptr<ObservableInstrument>(
-        new NoopObservableInstrument(name, description, unit));
+    return nostd::shared_ptr<ObservableUpDownCounter<double>>{
+        new NoopObservableUpDownCounter<double>(name, callback, description, unit)};
  }
 };

@ -239,33 +227,16 @@ class NoopMeterProvider final : public MeterProvider
 public:
  NoopMeterProvider() : meter_{nostd::shared_ptr<Meter>(new NoopMeter)} {}

-#if OPENTELEMETRY_ABI_VERSION_NO >= 2
-  nostd::shared_ptr<Meter> GetMeter(
-      nostd::string_view /* name */,
-      nostd::string_view /* version */,
-      nostd::string_view /* schema_url */,
-      const common::KeyValueIterable * /* attributes */) noexcept override
+  nostd::shared_ptr<Meter> GetMeter(nostd::string_view library_name,
+                                    nostd::string_view library_version,
+                                    nostd::string_view schema_url) noexcept override
  {
    return meter_;
  }
-#else
-  nostd::shared_ptr<Meter> GetMeter(nostd::string_view /* name */,
-                                    nostd::string_view /* version */,
-                                    nostd::string_view /* schema_url */) noexcept override
-  {
-    return meter_;
-  }
-#endif
-
-#if OPENTELEMETRY_ABI_VERSION_NO >= 2
-  void RemoveMeter(nostd::string_view /* name */,
-                   nostd::string_view /* version */,
-                   nostd::string_view /* schema_url */) noexcept override
-  {}
-#endif

 private:
  nostd::shared_ptr<Meter> meter_;
 };
 }  // namespace metrics
 OPENTELEMETRY_END_NAMESPACE
+#endif
--- a/api/include/opentelemetry/metrics/observer_result.h
+++ b/api/include/opentelemetry/metrics/observer_result.h
@ -2,40 +2,37 @@
 // SPDX-License-Identifier: Apache-2.0

 #pragma once
+#ifndef ENABLE_METRICS_PREVIEW

-#include "opentelemetry/common/attribute_value.h"
-#include "opentelemetry/common/key_value_iterable_view.h"
-#include "opentelemetry/nostd/shared_ptr.h"
-#include "opentelemetry/nostd/span.h"
-#include "opentelemetry/nostd/string_view.h"
-#include "opentelemetry/nostd/type_traits.h"
-#include "opentelemetry/nostd/variant.h"
-#include "opentelemetry/version.h"
+#  include "opentelemetry/common/attribute_value.h"
+#  include "opentelemetry/common/key_value_iterable_view.h"
+#  include "opentelemetry/nostd/span.h"
+#  include "opentelemetry/nostd/string_view.h"
+#  include "opentelemetry/nostd/type_traits.h"

 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace metrics
 {

 /**
- * ObserverResultT class is necessary for the callback recording asynchronous
+ * ObserverResult class is necessary for the callback recording asynchronous
 * instrument use.
 */
+
 template <class T>
-class ObserverResultT
+class ObserverResult
 {

 public:
-  virtual ~ObserverResultT() = default;
-
  virtual void Observe(T value) noexcept = 0;

-  virtual void Observe(T value, const common::KeyValueIterable &attributes) noexcept = 0;
+  virtual void Observer(T value, const common::KeyValueIterable &attributes) noexcept = 0;

  template <class U,
            nostd::enable_if_t<common::detail::is_key_value_iterable<U>::value> * = nullptr>
  void Observe(T value, const U &attributes) noexcept
  {
-    this->Observe(value, common::KeyValueIterableView<U>{attributes});
+    this->Observe(value, common::KeyValueIterableView<T>{attributes});
  }

  void Observe(T value,
@ -47,8 +44,6 @@ public:
  }
 };

-using ObserverResult = nostd::variant<nostd::shared_ptr<ObserverResultT<int64_t>>,
-                                      nostd::shared_ptr<ObserverResultT<double>>>;
-
 }  // namespace metrics
 OPENTELEMETRY_END_NAMESPACE
+#endif
--- a/api/include/opentelemetry/metrics/provider.h
+++ b/api/include/opentelemetry/metrics/provider.h
@ -2,19 +2,18 @@
 // SPDX-License-Identifier: Apache-2.0

 #pragma once
+#ifndef ENABLE_METRICS_PREVIEW

-#include <mutex>
+#  include <mutex>

-#include "opentelemetry/common/spin_lock_mutex.h"
-#include "opentelemetry/metrics/meter_provider.h"
-#include "opentelemetry/metrics/noop.h"
-#include "opentelemetry/nostd/shared_ptr.h"
-#include "opentelemetry/version.h"
+#  include "opentelemetry/common/spin_lock_mutex.h"
+#  include "opentelemetry/metrics/meter_provider.h"
+#  include "opentelemetry/metrics/noop.h"
+#  include "opentelemetry/nostd/shared_ptr.h"

 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace metrics
 {
-
 /**
 * Stores the singleton global MeterProvider.
 */
@ -36,20 +35,20 @@ public:
  /**
   * Changes the singleton MeterProvider.
   */
-  static void SetMeterProvider(const nostd::shared_ptr<MeterProvider> &tp) noexcept
+  static void SetMeterProvider(nostd::shared_ptr<MeterProvider> tp) noexcept
  {
    std::lock_guard<common::SpinLockMutex> guard(GetLock());
    GetProvider() = tp;
  }

 private:
-  OPENTELEMETRY_API_SINGLETON static nostd::shared_ptr<MeterProvider> &GetProvider() noexcept
+  static nostd::shared_ptr<MeterProvider> &GetProvider() noexcept
  {
    static nostd::shared_ptr<MeterProvider> provider(new NoopMeterProvider);
    return provider;
  }

-  OPENTELEMETRY_API_SINGLETON static common::SpinLockMutex &GetLock() noexcept
+  static common::SpinLockMutex &GetLock() noexcept
  {
    static common::SpinLockMutex lock;
    return lock;
@ -58,3 +57,4 @@ private:

 }  // namespace metrics
 OPENTELEMETRY_END_NAMESPACE
+#endif
--- a/api/include/opentelemetry/metrics/sync_instruments.h
+++ b/api/include/opentelemetry/metrics/sync_instruments.h
@ -2,67 +2,43 @@
 // SPDX-License-Identifier: Apache-2.0

 #pragma once
+#ifndef ENABLE_METRICS_PREVIEW

-#include "opentelemetry/common/attribute_value.h"
-#include "opentelemetry/common/key_value_iterable_view.h"
-#include "opentelemetry/context/context.h"
-#include "opentelemetry/nostd/span.h"
-#include "opentelemetry/nostd/string_view.h"
-#include "opentelemetry/nostd/type_traits.h"
-#include "opentelemetry/version.h"
+#  include "opentelemetry/common/attribute_value.h"
+#  include "opentelemetry/common/key_value_iterable_view.h"
+#  include "opentelemetry/nostd/span.h"
+#  include "opentelemetry/nostd/string_view.h"

 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace metrics
 {

 class SynchronousInstrument
-{
-public:
-  SynchronousInstrument()          = default;
-  virtual ~SynchronousInstrument() = default;
-};
+{};

-/* A Counter instrument that adds values. */
 template <class T>
 class Counter : public SynchronousInstrument
 {

 public:
  /**
-   * Record a value
+   * Add adds the value to the counter's sum
   *
   * @param value The increment amount. MUST be non-negative.
   */
  virtual void Add(T value) noexcept = 0;

  /**
-   * Record a value
+   * Add adds the value to the counter's sum. The attributes should contain
+   * the keys and values to be associated with this value.  Counters only
+   * accept positive valued updates.
   *
   * @param value The increment amount. MUST be non-negative.
-   * @param context The explicit context to associate with this measurement.
-   */
-  virtual void Add(T value, const context::Context &context) noexcept = 0;
-
-  /**
-   * Record a value with a set of attributes.
-   *
-   * @param value The increment amount. MUST be non-negative.
-   * @param attributes A set of attributes to associate with the value.
+   * @param attributes the set of attributes, as key-value pairs
   */

  virtual void Add(T value, const common::KeyValueIterable &attributes) noexcept = 0;

-  /**
-   * Record a value with a set of attributes.
-   *
-   * @param value The increment amount. MUST be non-negative.
-   * @param attributes A set of attributes to associate with the value.
-   * @param context The explicit context to associate with this measurement.
-   */
-  virtual void Add(T value,
-                   const common::KeyValueIterable &attributes,
-                   const context::Context &context) noexcept = 0;
-
  template <class U,
            nostd::enable_if_t<common::detail::is_key_value_iterable<U>::value> * = nullptr>
  void Add(T value, const U &attributes) noexcept
@ -70,13 +46,6 @@ public:
    this->Add(value, common::KeyValueIterableView<U>{attributes});
  }

-  template <class U,
-            nostd::enable_if_t<common::detail::is_key_value_iterable<U>::value> * = nullptr>
-  void Add(T value, const U &attributes, const context::Context &context) noexcept
-  {
-    this->Add(value, common::KeyValueIterableView<U>{attributes}, context);
-  }
-
  void Add(T value,
           std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>>
               attributes) noexcept
@ -84,16 +53,6 @@ public:
    this->Add(value, nostd::span<const std::pair<nostd::string_view, common::AttributeValue>>{
                         attributes.begin(), attributes.end()});
  }
-
-  void Add(T value,
-           std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>> attributes,
-           const context::Context &context) noexcept
-  {
-    this->Add(value,
-              nostd::span<const std::pair<nostd::string_view, common::AttributeValue>>{
-                  attributes.begin(), attributes.end()},
-              context);
-  }
 };

 /** A histogram instrument that records values. */
@ -102,23 +61,20 @@ template <class T>
 class Histogram : public SynchronousInstrument
 {
 public:
-#if OPENTELEMETRY_ABI_VERSION_NO >= 2
  /**
-   * @since ABI_VERSION 2
   * Records a value.
   *
-   * @param value The measurement value. MUST be non-negative.
+   * @param value The increment amount. May be positive, negative or zero.
   */
  virtual void Record(T value) noexcept = 0;

  /**
-   * @since ABI_VERSION 2
   * Records a value with a set of attributes.
   *
-   * @param value The measurement value. MUST be non-negative.
-   * @param attribute A set of attributes to associate with the value.
+   * @param value The increment amount. May be positive, negative or zero.
+   * @param attributes A set of attributes to associate with the count.
   */
-  virtual void Record(T value, const common::KeyValueIterable &attribute) noexcept = 0;
+  virtual void Record(T value, const common::KeyValueIterable &attributes) noexcept = 0;

  template <class U,
            nostd::enable_if_t<common::detail::is_key_value_iterable<U>::value> * = nullptr>
@ -134,44 +90,6 @@ public:
    this->Record(value, nostd::span<const std::pair<nostd::string_view, common::AttributeValue>>{
                            attributes.begin(), attributes.end()});
  }
-#endif
-
-  /**
-   * Records a value.
-   *
-   * @param value The measurement value. MUST be non-negative.
-   * @param context The explicit context to associate with this measurement.
-   */
-  virtual void Record(T value, const context::Context &context) noexcept = 0;
-
-  /**
-   * Records a value with a set of attributes.
-   *
-   * @param value The measurement value. MUST be non-negative.
-   * @param attributes A set of attributes to associate with the value..
-   * @param context The explicit context to associate with this measurement.
-   */
-  virtual void Record(T value,
-                      const common::KeyValueIterable &attributes,
-                      const context::Context &context) noexcept = 0;
-
-  template <class U,
-            nostd::enable_if_t<common::detail::is_key_value_iterable<U>::value> * = nullptr>
-  void Record(T value, const U &attributes, const context::Context &context) noexcept
-  {
-    this->Record(value, common::KeyValueIterableView<U>{attributes}, context);
-  }
-
-  void Record(
-      T value,
-      std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>> attributes,
-      const context::Context &context) noexcept
-  {
-    this->Record(value,
-                 nostd::span<const std::pair<nostd::string_view, common::AttributeValue>>{
-                     attributes.begin(), attributes.end()},
-                 context);
-  }
 };

 /** An up-down-counter instrument that adds or reduce values. */
@ -181,39 +99,20 @@ class UpDownCounter : public SynchronousInstrument
 {
 public:
  /**
-   * Record a value.
+   * Adds a value.
   *
-   * @param value The increment amount. May be positive, negative or zero.
+   * @param value The amount of the measurement.
   */
  virtual void Add(T value) noexcept = 0;

  /**
-   * Record a value.
-   *
-   * @param value The increment amount. May be positive, negative or zero.
-   * @param context The explicit context to associate with this measurement.
-   */
-  virtual void Add(T value, const context::Context &context) noexcept = 0;
-
-  /**
-   * Record a value with a set of attributes.
+   * Add a value with a set of attributes.
   *
   * @param value The increment amount. May be positive, negative or zero.
   * @param attributes A set of attributes to associate with the count.
   */
  virtual void Add(T value, const common::KeyValueIterable &attributes) noexcept = 0;

-  /**
-   * Record a value with a set of attributes.
-   *
-   * @param value The increment amount. May be positive, negative or zero.
-   * @param attributes A set of attributes to associate with the count.
-   * @param context The explicit context to associate with this measurement.
-   */
-  virtual void Add(T value,
-                   const common::KeyValueIterable &attributes,
-                   const context::Context &context) noexcept = 0;
-
  template <class U,
            nostd::enable_if_t<common::detail::is_key_value_iterable<U>::value> * = nullptr>
  void Add(T value, const U &attributes) noexcept
@ -221,13 +120,6 @@ public:
    this->Add(value, common::KeyValueIterableView<U>{attributes});
  }

-  template <class U,
-            nostd::enable_if_t<common::detail::is_key_value_iterable<U>::value> * = nullptr>
-  void Add(T value, const U &attributes, const context::Context &context) noexcept
-  {
-    this->Add(value, common::KeyValueIterableView<U>{attributes}, context);
-  }
-
  void Add(T value,
           std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>>
               attributes) noexcept
@ -235,94 +127,8 @@ public:
    this->Add(value, nostd::span<const std::pair<nostd::string_view, common::AttributeValue>>{
                         attributes.begin(), attributes.end()});
  }
-
-  void Add(T value,
-           std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>> attributes,
-           const context::Context &context) noexcept
-  {
-    this->Add(value,
-              nostd::span<const std::pair<nostd::string_view, common::AttributeValue>>{
-                  attributes.begin(), attributes.end()},
-              context);
-  }
 };

-#if OPENTELEMETRY_ABI_VERSION_NO >= 2
-/* A Gauge instrument that records values. */
-template <class T>
-class Gauge : public SynchronousInstrument
-{
-
-public:
-  /**
-   * Record a value
-   *
-   * @param value The measurement value. May be positive, negative or zero.
-   */
-  virtual void Record(T value) noexcept = 0;
-
-  /**
-   * Record a value
-   *
-   * @param value The measurement value. May be positive, negative or zero.
-   * @param context The explicit context to associate with this measurement.
-   */
-  virtual void Record(T value, const context::Context &context) noexcept = 0;
-
-  /**
-   * Record a value with a set of attributes.
-   *
-   * @param value The measurement value. May be positive, negative or zero.
-   * @param attributes A set of attributes to associate with the value.
-   */
-
-  virtual void Record(T value, const common::KeyValueIterable &attributes) noexcept = 0;
-
-  /**
-   * Record a value with a set of attributes.
-   *
-   * @param value The measurement value. May be positive, negative or zero.
-   * @param attributes A set of attributes to associate with the value.
-   * @param context The explicit context to associate with this measurement.
-   */
-  virtual void Record(T value,
-                      const common::KeyValueIterable &attributes,
-                      const context::Context &context) noexcept = 0;
-
-  template <class U,
-            nostd::enable_if_t<common::detail::is_key_value_iterable<U>::value> * = nullptr>
-  void Record(T value, const U &attributes) noexcept
-  {
-    this->Record(value, common::KeyValueIterableView<U>{attributes});
-  }
-
-  template <class U,
-            nostd::enable_if_t<common::detail::is_key_value_iterable<U>::value> * = nullptr>
-  void Record(T value, const U &attributes, const context::Context &context) noexcept
-  {
-    this->Record(value, common::KeyValueIterableView<U>{attributes}, context);
-  }
-
-  void Record(T value,
-              std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>>
-                  attributes) noexcept
-  {
-    this->Record(value, nostd::span<const std::pair<nostd::string_view, common::AttributeValue>>{
-                            attributes.begin(), attributes.end()});
-  }
-
-  void Record(
-      T value,
-      std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>> attributes,
-      const context::Context &context) noexcept
-  {
-    this->Record(value,
-                 nostd::span<const std::pair<nostd::string_view, common::AttributeValue>>{
-                     attributes.begin(), attributes.end()},
-                 context);
-  }
-};
-#endif
-
 }  // namespace metrics
 OPENTELEMETRY_END_NAMESPACE
+#endif
--- a/api/include/opentelemetry/nostd/internal/absl/.clang-format
+++ b/api/include/opentelemetry/nostd/internal/absl/.clang-format
--- a/api/include/opentelemetry/nostd/absl/README.md
+++ b/api/include/opentelemetry/nostd/absl/README.md
@ -0,0 +1,4 @@
+# Notes on Abseil Variant implementation
+
+This is a snapshot of Abseil Variant `absl::variant` from Abseil
+`v2020-03-03#8`.
--- a/api/include/opentelemetry/nostd/internal/absl/base/attributes.h
+++ b/api/include/opentelemetry/nostd/internal/absl/base/attributes.h
--- a/api/include/opentelemetry/nostd/internal/absl/base/config.h
+++ b/api/include/opentelemetry/nostd/internal/absl/base/config.h
@ -84,7 +84,7 @@
 // namespace absl {
 // OTABSL_NAMESPACE_BEGIN
 //
-// void Foo();  // absl::OTABSL_OPTION_NAMESPACE_NAME::Foo().
+// void Foo();  // absl::Foo().
 //
 // OTABSL_NAMESPACE_END
 // }  // namespace absl
@ -94,32 +94,40 @@
 // not support forward declarations of its own types, nor does it support
 // user-provided specialization of Abseil templates.  Code that violates these
 // rules may be broken without warning.)
-#if !defined(OTABSL_OPTION_NAMESPACE_NAME)
+#if !defined(OTABSL_OPTION_USE_INLINE_NAMESPACE) || \
+    !defined(OTABSL_OPTION_INLINE_NAMESPACE_NAME)
 #error options.h is misconfigured.
 #endif

-// Check that OTABSL_OPTION_NAMESPACE_NAME is neither "head" nor ""
-#if defined(__cplusplus)
+// Check that OTABSL_OPTION_INLINE_NAMESPACE_NAME is neither "head" nor ""
+#if defined(__cplusplus) && OTABSL_OPTION_USE_INLINE_NAMESPACE == 1

 #define OTABSL_INTERNAL_INLINE_NAMESPACE_STR \
-  OTABSL_INTERNAL_TOKEN_STR(OTABSL_OPTION_NAMESPACE_NAME)
+  OTABSL_INTERNAL_TOKEN_STR(OTABSL_OPTION_INLINE_NAMESPACE_NAME)

 static_assert(OTABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != '\0',
-              "options.h misconfigured: OTABSL_OPTION_NAMESPACE_NAME must "
+              "options.h misconfigured: OTABSL_OPTION_INLINE_NAMESPACE_NAME must "
              "not be empty.");
 static_assert(OTABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != 'h' ||
                  OTABSL_INTERNAL_INLINE_NAMESPACE_STR[1] != 'e' ||
                  OTABSL_INTERNAL_INLINE_NAMESPACE_STR[2] != 'a' ||
                  OTABSL_INTERNAL_INLINE_NAMESPACE_STR[3] != 'd' ||
                  OTABSL_INTERNAL_INLINE_NAMESPACE_STR[4] != '\0',
-              "options.h misconfigured: OTABSL_OPTION_NAMESPACE_NAME must "
+              "options.h misconfigured: OTABSL_OPTION_INLINE_NAMESPACE_NAME must "
              "be changed to a new, unique identifier name.");

 #endif

-
-#define OTABSL_NAMESPACE_BEGIN namespace OTABSL_OPTION_NAMESPACE_NAME {
+#if OTABSL_OPTION_USE_INLINE_NAMESPACE == 0
+#define OTABSL_NAMESPACE_BEGIN
+#define OTABSL_NAMESPACE_END
+#elif OTABSL_OPTION_USE_INLINE_NAMESPACE == 1
+#define OTABSL_NAMESPACE_BEGIN \
+  inline namespace OTABSL_OPTION_INLINE_NAMESPACE_NAME {
 #define OTABSL_NAMESPACE_END }
+#else
+#error options.h is misconfigured.
+#endif

 // -----------------------------------------------------------------------------
 // Compiler Feature Checks
@ -164,7 +172,6 @@ static_assert(OTABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != 'h' ||
 #ifdef OTABSL_HAVE_STD_IS_TRIVIALLY_DESTRUCTIBLE
 #error OTABSL_HAVE_STD_IS_TRIVIALLY_DESTRUCTIBLE cannot be directly set
 #elif defined(_LIBCPP_VERSION) ||                                        \
-    (defined(__clang__) && __clang_major__ >= 15) ||                     \
    (!defined(__clang__) && defined(__GNUC__) && defined(__GLIBCXX__) && \
     (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8))) ||        \
    defined(_MSC_VER)
@ -187,7 +194,6 @@ static_assert(OTABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != 'h' ||
 #elif defined(OTABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE)
 #error OTABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE cannot directly set
 #elif (defined(__clang__) && defined(_LIBCPP_VERSION)) ||        \
-    (defined(__clang__) && __clang_major__ >= 15) ||             \
    (!defined(__clang__) && defined(__GNUC__) &&                 \
     (__GNUC__ > 7 || (__GNUC__ == 7 && __GNUC_MINOR__ >= 4)) && \
     (defined(_LIBCPP_VERSION) || defined(__GLIBCXX__))) ||      \
@ -196,20 +202,9 @@ static_assert(OTABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != 'h' ||
 #define OTABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE 1
 #endif

-// OTABSL_HAVE_STD_IS_TRIVIALLY_COPYABLE
-//
-// Checks whether `std::is_trivially_copyable<T>` is supported.
-//
-// Notes: Clang 15+ with libc++ supports these features, GCC hasn't been tested.
-#if defined(OTABSL_HAVE_STD_IS_TRIVIALLY_COPYABLE)
-#error OTABSL_HAVE_STD_IS_TRIVIALLY_COPYABLE cannot be directly set
-#elif defined(__clang__) && (__clang_major__ >= 15)
-#define OTABSL_HAVE_STD_IS_TRIVIALLY_COPYABLE 1
-#endif
-
 // OTABSL_HAVE_SOURCE_LOCATION_CURRENT
 //
-// Indicates whether `absl::OTABSL_OPTION_NAMESPACE_NAME::SourceLocation::current()` will return useful
+// Indicates whether `absl::SourceLocation::current()` will return useful
 // information in some contexts.
 #ifndef OTABSL_HAVE_SOURCE_LOCATION_CURRENT
 #if OTABSL_INTERNAL_HAS_KEYWORD(__builtin_LINE) && \
@ -562,7 +557,7 @@ static_assert(OTABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != 'h' ||

 // OTABSL_USES_STD_ANY
 //
-// Indicates whether absl::OTABSL_OPTION_NAMESPACE_NAME::any is an alias for std::any.
+// Indicates whether absl::any is an alias for std::any.
 #if !defined(OTABSL_OPTION_USE_STD_ANY)
 #error options.h is misconfigured.
 #elif OTABSL_OPTION_USE_STD_ANY == 0 || \
@ -577,7 +572,7 @@ static_assert(OTABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != 'h' ||

 // OTABSL_USES_STD_OPTIONAL
 //
-// Indicates whether absl::OTABSL_OPTION_NAMESPACE_NAME::optional is an alias for std::optional.
+// Indicates whether absl::optional is an alias for std::optional.
 #if !defined(OTABSL_OPTION_USE_STD_OPTIONAL)
 #error options.h is misconfigured.
 #elif OTABSL_OPTION_USE_STD_OPTIONAL == 0 || \
@ -592,7 +587,7 @@ static_assert(OTABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != 'h' ||

 // OTABSL_USES_STD_VARIANT
 //
-// Indicates whether absl::OTABSL_OPTION_NAMESPACE_NAME::variant is an alias for std::variant.
+// Indicates whether absl::variant is an alias for std::variant.
 #if !defined(OTABSL_OPTION_USE_STD_VARIANT)
 #error options.h is misconfigured.
 #elif OTABSL_OPTION_USE_STD_VARIANT == 0 || \
@ -607,7 +602,7 @@ static_assert(OTABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != 'h' ||

 // OTABSL_USES_STD_STRING_VIEW
 //
-// Indicates whether absl::OTABSL_OPTION_NAMESPACE_NAME::string_view is an alias for std::string_view.
+// Indicates whether absl::string_view is an alias for std::string_view.
 #if !defined(OTABSL_OPTION_USE_STD_STRING_VIEW)
 #error options.h is misconfigured.
 #elif OTABSL_OPTION_USE_STD_STRING_VIEW == 0 || \
@ -642,10 +637,15 @@ static_assert(OTABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != 'h' ||
 // the proper count to skip past the CCTZ fork namespace names.  (This number
 // is one larger when there is an inline namespace name to skip.)
 #if defined(_MSC_VER)
+#if OTABSL_OPTION_USE_INLINE_NAMESPACE == 0
+#define OTABSL_INTERNAL_MANGLED_NS "absl"
+#define OTABSL_INTERNAL_MANGLED_BACKREFERENCE "5"
+#else
 #define OTABSL_INTERNAL_MANGLED_NS \
-  OTABSL_INTERNAL_TOKEN_STR(OTABSL_OPTION_NAMESPACE_NAME) "@absl"
+  OTABSL_INTERNAL_TOKEN_STR(OTABSL_OPTION_INLINE_NAMESPACE_NAME) "@absl"
 #define OTABSL_INTERNAL_MANGLED_BACKREFERENCE "6"
 #endif
+#endif

 #undef OTABSL_INTERNAL_HAS_KEYWORD

--- a/api/include/opentelemetry/nostd/internal/absl/base/internal/identity.h
+++ b/api/include/opentelemetry/nostd/internal/absl/base/internal/identity.h
--- a/api/include/opentelemetry/nostd/internal/absl/base/internal/inline_variable.h
+++ b/api/include/opentelemetry/nostd/internal/absl/base/internal/inline_variable.h
@ -68,7 +68,7 @@
 //   types, etc..
 #if defined(__clang__)
 #define OTABSL_INTERNAL_EXTERN_DECL(type, name) \
-  extern const ::absl::OTABSL_OPTION_NAMESPACE_NAME::internal::identity_t<type> name;
+  extern const ::absl::OTABSL_OPTION_INLINE_NAMESPACE_NAME::internal::identity_t<type> name;
 #else  // Otherwise, just define the macro to do nothing.
 #define OTABSL_INTERNAL_EXTERN_DECL(type, name)
 #endif  // defined(__clang__)
@ -76,7 +76,7 @@
 // See above comment at top of file for details.
 #define OTABSL_INTERNAL_INLINE_CONSTEXPR(type, name, init) \
  OTABSL_INTERNAL_EXTERN_DECL(type, name)                  \
-  inline constexpr ::absl::OTABSL_OPTION_NAMESPACE_NAME::internal::identity_t<type> name = init
+  inline constexpr ::absl::OTABSL_OPTION_INLINE_NAMESPACE_NAME::internal::identity_t<type> name = init

 #else

@ -89,14 +89,14 @@
 #define OTABSL_INTERNAL_INLINE_CONSTEXPR(var_type, name, init)                  \
  template <class /*AbslInternalDummy*/ = void>                               \
  struct AbslInternalInlineVariableHolder##name {                             \
-    static constexpr ::absl::OTABSL_OPTION_NAMESPACE_NAME::internal::identity_t<var_type> kInstance = init; \
+    static constexpr ::absl::OTABSL_OPTION_INLINE_NAMESPACE_NAME::internal::identity_t<var_type> kInstance = init; \
  };                                                                          \
                                                                              \
  template <class AbslInternalDummy>                                          \
-  constexpr ::absl::OTABSL_OPTION_NAMESPACE_NAME::internal::identity_t<var_type>                            \
+  constexpr ::absl::OTABSL_OPTION_INLINE_NAMESPACE_NAME::internal::identity_t<var_type>                            \
      AbslInternalInlineVariableHolder##name<AbslInternalDummy>::kInstance;   \
                                                                              \
-  static constexpr const ::absl::OTABSL_OPTION_NAMESPACE_NAME::internal::identity_t<var_type>&              \
+  static constexpr const ::absl::OTABSL_OPTION_INLINE_NAMESPACE_NAME::internal::identity_t<var_type>&              \
      name = /* NOLINT */                                                     \
      AbslInternalInlineVariableHolder##name<>::kInstance;                    \
  static_assert(sizeof(void (*)(decltype(name))) != 0,                        \
--- a/Show More
+++ b/Show More
 @ -1 +1 @@
 .1.1
 .2.0