diff --git a/dd-java-agent-ittests/dd-java-agent-ittests.gradle b/dd-java-agent-ittests/dd-java-agent-ittests.gradle
index dcf2438223..dcc11adeb9 100644
--- a/dd-java-agent-ittests/dd-java-agent-ittests.gradle
+++ b/dd-java-agent-ittests/dd-java-agent-ittests.gradle
@@ -52,7 +52,7 @@ test {
   }
 
   if (project.hasProperty("disableShadowRelocate") && disableShadowRelocate) {
-    exclude 'datadog/trace/agent/ShadowPackageRenamingTest.class'
+    exclude 'datadog/trace/agent/integration/classloading/ShadowPackageRenamingTest.class'
   }
 }
 
diff --git a/dd-trace-ot/src/main/java/datadog/trace/common/writer/DDApi.java b/dd-trace-ot/src/main/java/datadog/trace/common/writer/DDApi.java
index 8759d4efdb..ca455a95aa 100644
--- a/dd-trace-ot/src/main/java/datadog/trace/common/writer/DDApi.java
+++ b/dd-trace-ot/src/main/java/datadog/trace/common/writer/DDApi.java
@@ -10,10 +10,10 @@ import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStreamReader;
 import java.io.OutputStream;
-import java.io.OutputStreamWriter;
 import java.net.HttpURLConnection;
 import java.net.URL;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
@@ -40,8 +40,8 @@ public class DDApi {
   private final ObjectMapper objectMapper = new ObjectMapper(new MessagePackFactory());
 
   public DDApi(final String host, final int port) {
-    if (endpointAvailable("http://" + host + ":" + port + TRACES_ENDPOINT_V4)
-        && endpointAvailable("http://" + host + ":" + port + SERVICES_ENDPOINT_V4)) {
+    if (traceEndpointAvailable("http://" + host + ":" + port + TRACES_ENDPOINT_V4)
+        && serviceEndpointAvailable("http://" + host + ":" + port + SERVICES_ENDPOINT_V4)) {
       this.tracesEndpoint = "http://" + host + ":" + port + TRACES_ENDPOINT_V4;
       this.servicesEndpoint = "http://" + host + ":" + port + SERVICES_ENDPOINT_V4;
     } else {
@@ -163,11 +163,15 @@ public class DDApi {
     }
   }
 
-  private boolean endpointAvailable(final String endpoint) {
-    return endpointAvailable(endpoint, true);
+  private boolean traceEndpointAvailable(final String endpoint) {
+    return endpointAvailable(endpoint, Collections.emptyList(), true);
   }
 
-  private boolean endpointAvailable(final String endpoint, final boolean retry) {
+  private boolean serviceEndpointAvailable(final String endpoint) {
+    return endpointAvailable(endpoint, Collections.emptyMap(), true);
+  }
+
+  private boolean endpointAvailable(final String endpoint, final Object data, final boolean retry) {
     try {
       final HttpURLConnection httpCon = getHttpURLConnection(endpoint);
 
@@ -175,13 +179,14 @@ public class DDApi {
       httpCon.setConnectTimeout((int) TimeUnit.SECONDS.toMillis(1));
       httpCon.setReadTimeout((int) TimeUnit.SECONDS.toMillis(1));
 
-      final OutputStreamWriter out = new OutputStreamWriter(httpCon.getOutputStream());
+      final OutputStream out = httpCon.getOutputStream();
+      objectMapper.writeValue(out, data);
       out.flush();
       out.close();
       return httpCon.getResponseCode() == 200;
     } catch (final IOException e) {
       if (retry) {
-        return endpointAvailable(endpoint, false);
+        return endpointAvailable(endpoint, data, false);
       }
     }
     return false;
diff --git a/dd-trace-ot/src/test/groovy/datadog/trace/api/writer/DDApiTest.groovy b/dd-trace-ot/src/test/groovy/datadog/trace/api/writer/DDApiTest.groovy
index b7de75569b..19cae1be62 100644
--- a/dd-trace-ot/src/test/groovy/datadog/trace/api/writer/DDApiTest.groovy
+++ b/dd-trace-ot/src/test/groovy/datadog/trace/api/writer/DDApiTest.groovy
@@ -30,10 +30,12 @@ class DDApiTest extends Specification {
     def agent = ratpack {
       handlers {
         put("v0.4/traces") {
-          response.status(200).send()
+          def status = request.contentLength > 0 ? 200 : 500
+          response.status(status).send()
         }
         put("v0.4/services") {
-          response.status(200).send()
+          def status = request.contentLength > 0 ? 200 : 500
+          response.status(status).send()
         }
       }
     }
@@ -56,7 +58,8 @@ class DDApiTest extends Specification {
           response.status(404).send()
         }
         put("v0.4/services") {
-          response.status(200).send()
+          def status = request.contentLength > 0 ? 200 : 500
+          response.status(status).send()
         }
       }
     }
@@ -87,7 +90,8 @@ class DDApiTest extends Specification {
           }
         }
         put("v0.4/services") {
-          response.status(200).send()
+          def status = request.contentLength > 0 ? 200 : 500
+          response.status(status).send()
         }
       }
     }
@@ -144,10 +148,12 @@ class DDApiTest extends Specification {
     def agent = ratpack {
       handlers {
         put("v0.4/traces") {
-          response.status(200).send()
+          def status = request.contentLength > 0 ? 200 : 500
+          response.status(status).send()
         }
         put("v0.4/services") {
-          response.status(200).send()
+          def status = request.contentLength > 0 ? 200 : 500
+          response.status(status).send()
         }
       }
     }
@@ -167,7 +173,8 @@ class DDApiTest extends Specification {
     def agent = ratpack {
       handlers {
         put("v0.4/traces") {
-          response.status(200).send()
+          def status = request.contentLength > 0 ? 200 : 500
+          response.status(status).send()
         }
         put("v0.4/services") {
           response.status(404).send()
@@ -193,7 +200,8 @@ class DDApiTest extends Specification {
     def agent = ratpack {
       handlers {
         put("v0.4/traces") {
-          response.status(200).send()
+          def status = request.contentLength > 0 ? 200 : 500
+          response.status(status).send()
         }
         put("v0.4/services") {
           requestContentType.set(request.contentType)
@@ -243,11 +251,13 @@ class DDApiTest extends Specification {
     def agent = ratpack {
       handlers {
         put("v0.4/traces") {
-          response.status(200).send('{"hello":"test"}')
+          def status = request.contentLength > 0 ? 200 : 500
+          response.status(status).send('{"hello":"test"}')
         }
         put("v0.4/services") {
           if (servicesAvailable) {
-            response.status(200).send('{"service-response":"from-test"}')
+            def status = request.contentLength > 0 ? 200 : 500
+            response.status(status).send('{"service-response":"from-test"}')
           } else {
             response.status(404).send('{"service-response":"from-test"}')
           }
@@ -280,10 +290,12 @@ class DDApiTest extends Specification {
     def v3Agent = ratpack {
       handlers {
         put("v0.3/traces") {
-          response.status(200).send()
+          def status = request.contentLength > 0 ? 200 : 500
+          response.status(status).send()
         }
         put("v0.3/services") {
-          response.status(200).send()
+          def status = request.contentLength > 0 ? 200 : 500
+          response.status(status).send()
         }
       }
     }
@@ -307,21 +319,25 @@ class DDApiTest extends Specification {
     def agent = ratpack {
       handlers {
         put("v0.3/traces") {
-          response.status(200).send()
+          def status = request.contentLength > 0 ? 200 : 500
+          response.status(status).send()
         }
         put("v0.3/services") {
-          response.status(200).send()
+          def status = request.contentLength > 0 ? 200 : 500
+          response.status(status).send()
         }
         put("v0.4/traces") {
           Blocking.exec {
             Thread.sleep(delayTrace)
-            response.status(200).send()
+            def status = request.contentLength > 0 ? 200 : 500
+            response.status(status).send()
           }
         }
         put("v0.4/services") {
           Blocking.exec {
             Thread.sleep(delayServices)
-            response.status(200).send()
+            def status = request.contentLength > 0 ? 200 : 500
+            response.status(status).send()
           }
         }
       }