diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..abe6797
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,4 @@
+[submodule "conformance"]
+	path = conformance
+	url = https://github.com/cloudevents/conformance.git
+	branch = format-tests
diff --git a/conformance b/conformance
new file mode 160000
index 0000000..c5bcce2
--- /dev/null
+++ b/conformance
@@ -0,0 +1 @@
+Subproject commit c5bcce28fa078aeef41e5b1998a7c01270d62d35