diff --git a/engine/core/script/dart_controller.cc b/engine/core/script/dart_controller.cc
index ba08c15dada..039e36ac353 100644
--- a/engine/core/script/dart_controller.cc
+++ b/engine/core/script/dart_controller.cc
@@ -11,6 +11,7 @@
 #include "base/trace_event/trace_event.h"
 #include "dart/runtime/bin/embedded_dart_io.h"
 #include "dart/runtime/include/dart_mirrors_api.h"
+#include "gen/sky/platform/RuntimeEnabledFeatures.h"
 #include "sky/engine/bindings/builtin.h"
 #include "sky/engine/bindings/builtin_natives.h"
 #include "sky/engine/bindings/builtin_sky.h"
@@ -257,11 +258,13 @@ static Dart_Isolate IsolateCreateCallback(const char* script_uri,
       // Start the handle watcher from the service isolate so it isn't available
       // for debugging or general Observatory interaction.
       EnsureHandleWatcherStarted();
-      std::string ip = "127.0.0.1";
-      const intptr_t port = 8181;
-      const bool service_isolate_booted =
-          DartServiceIsolate::Startup(ip, port, LibraryTagHandler, error);
-      CHECK(service_isolate_booted) << error;
+      if (RuntimeEnabledFeatures::observatoryEnabled()) {
+        std::string ip = "127.0.0.1";
+        const intptr_t port = 8181;
+        const bool service_isolate_booted =
+            DartServiceIsolate::Startup(ip, port, LibraryTagHandler, error);
+        CHECK(service_isolate_booted) << error;
+      }
     }
     Dart_ExitIsolate();
     return isolate;
diff --git a/engine/platform/RuntimeEnabledFeatures.in b/engine/platform/RuntimeEnabledFeatures.in
index 0e204814e77..e891706ae19 100644
--- a/engine/platform/RuntimeEnabledFeatures.in
+++ b/engine/platform/RuntimeEnabledFeatures.in
@@ -118,3 +118,5 @@ WOFF2 status=stable
 PseudoClassesInMatchingCriteriaInAuthorShadowTrees status=test
 
 CredentialManager status=test
+
+Observatory status=stable
diff --git a/engine/public/web/WebRuntimeFeatures.h b/engine/public/web/WebRuntimeFeatures.h
index 8a46290030e..9a9dd9ba62a 100644
--- a/engine/public/web/WebRuntimeFeatures.h
+++ b/engine/public/web/WebRuntimeFeatures.h
@@ -94,6 +94,8 @@ public:
 
     BLINK_EXPORT static void enableLaxMixedContentChecking(bool);
 
+    BLINK_EXPORT static void enableObservatory(bool);
+
 private:
     WebRuntimeFeatures();
 };
diff --git a/engine/web/WebRuntimeFeatures.cpp b/engine/web/WebRuntimeFeatures.cpp
index a01e247afd0..46b02087d1d 100644
--- a/engine/web/WebRuntimeFeatures.cpp
+++ b/engine/web/WebRuntimeFeatures.cpp
@@ -176,4 +176,9 @@ void WebRuntimeFeatures::enableLaxMixedContentChecking(bool enable)
     RuntimeEnabledFeatures::setLaxMixedContentCheckingEnabled(enable);
 }
 
+void WebRuntimeFeatures::enableObservatory(bool enable)
+{
+    RuntimeEnabledFeatures::setObservatoryEnabled(enable);
+}
+
 } // namespace blink
diff --git a/viewer/viewer.cc b/viewer/viewer.cc
index 2461fa6f05e..ce3f949b017 100644
--- a/viewer/viewer.cc
+++ b/viewer/viewer.cc
@@ -15,6 +15,7 @@
 #include "mojo/public/cpp/application/interface_factory_impl.h"
 #include "mojo/services/content_handler/public/interfaces/content_handler.mojom.h"
 #include "sky/engine/public/web/Sky.h"
+#include "sky/engine/public/web/WebRuntimeFeatures.h"
 #include "sky/services/platform/platform_impl.h"
 #include "sky/viewer/content_handler_impl.h"
 #include "sky/viewer/document_view.h"
@@ -34,6 +35,8 @@ class Viewer : public mojo::ApplicationDelegate,
   void Initialize(mojo::ApplicationImpl* app) override {
     RuntimeFlags::Initialize(app);
 
+    blink::WebRuntimeFeatures::enableObservatory(!RuntimeFlags::Get().testing());
+
     mojo::NetworkServicePtr network_service;
     app->ConnectToService("mojo:network_service", &network_service);
     platform_impl_.reset(new PlatformImpl(network_service.Pass()));