diff --git a/src/isomorphic/ReactDebugTool.js b/src/isomorphic/ReactDebugTool.js
new file mode 100644
index 000000000000..2435a613f400
--- /dev/null
+++ b/src/isomorphic/ReactDebugTool.js
@@ -0,0 +1,65 @@
+/**
+ * Copyright 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ * @providesModule ReactDebugTool
+ */
+
+'use strict';
+
+var warning = require('warning');
+
+var eventHandlers = [];
+var handlerDoesThrowForEvent = {};
+
+function emitEvent(handlerFunctionName, arg1, arg2, arg3, arg4, arg5) {
+  if (__DEV__) {
+    eventHandlers.forEach(function(handler) {
+      try {
+        if (handler[handlerFunctionName]) {
+          handler[handlerFunctionName](arg1, arg2, arg3, arg4, arg5);
+        }
+      } catch (e) {
+        warning(
+          !handlerDoesThrowForEvent[handlerFunctionName],
+          'exception thrown by devtool while handling %s: %s',
+          handlerFunctionName,
+          e.message
+        );
+        handlerDoesThrowForEvent[handlerFunctionName] = true;
+      }
+    });
+  }
+}
+
+var ReactDebugTool = {
+  addDevtool(devtool) {
+    eventHandlers.push(devtool);
+  },
+  removeDevtool(devtool) {
+    for (var i = 0; i < eventHandlers.length; i++) {
+      if (eventHandlers[i] === devtool) {
+        eventHandlers.splice(i, 1);
+        i--;
+      }
+    }
+  },
+  onMountRootComponent(internalInstance) {
+    emitEvent('onMountRootComponent', internalInstance);
+  },
+  onMountComponent(internalInstance) {
+    emitEvent('onMountComponent', internalInstance);
+  },
+  onUpdateComponent(internalInstance) {
+    emitEvent('onUpdateComponent', internalInstance);
+  },
+  onUnmountComponent(internalInstance) {
+    emitEvent('onUnmountComponent', internalInstance);
+  },
+};
+
+module.exports = ReactDebugTool;
diff --git a/src/isomorphic/ReactInstrumentation.js b/src/isomorphic/ReactInstrumentation.js
new file mode 100644
index 000000000000..066da6aaae82
--- /dev/null
+++ b/src/isomorphic/ReactInstrumentation.js
@@ -0,0 +1,16 @@
+/**
+ * Copyright 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ * @providesModule ReactInstrumentation
+ */
+
+'use strict';
+
+var ReactDebugTool = require('ReactDebugTool');
+
+module.exports = {debugTool: ReactDebugTool};
diff --git a/src/renderers/dom/client/ReactMount.js b/src/renderers/dom/client/ReactMount.js
index ea62047b0aba..4b11559670cd 100644
--- a/src/renderers/dom/client/ReactMount.js
+++ b/src/renderers/dom/client/ReactMount.js
@@ -20,6 +20,7 @@ var ReactDOMContainerInfo = require('ReactDOMContainerInfo');
 var ReactDOMFeatureFlags = require('ReactDOMFeatureFlags');
 var ReactElement = require('ReactElement');
 var ReactFeatureFlags = require('ReactFeatureFlags');
+var ReactInstrumentation = require('ReactInstrumentation');
 var ReactMarkupChecksum = require('ReactMarkupChecksum');
 var ReactPerf = require('ReactPerf');
 var ReactReconciler = require('ReactReconciler');
@@ -347,6 +348,10 @@ var ReactMount = {
     var wrapperID = componentInstance._instance.rootID;
     instancesByReactRootID[wrapperID] = componentInstance;
 
+    if (__DEV__) {
+      ReactInstrumentation.debugTool.onMountRootComponent(componentInstance);
+    }
+
     return componentInstance;
   },
 
diff --git a/src/renderers/shared/reconciler/ReactReconciler.js b/src/renderers/shared/reconciler/ReactReconciler.js
index 507d351612a9..ae7806e4fc0e 100644
--- a/src/renderers/shared/reconciler/ReactReconciler.js
+++ b/src/renderers/shared/reconciler/ReactReconciler.js
@@ -12,6 +12,7 @@
 'use strict';
 
 var ReactRef = require('ReactRef');
+var ReactInstrumentation = require('ReactInstrumentation');
 
 /**
  * Helper to call ReactRef.attachRefs with this composite component, split out
@@ -51,6 +52,9 @@ var ReactReconciler = {
         internalInstance._currentElement.ref != null) {
       transaction.getReactMountReady().enqueue(attachRefs, internalInstance);
     }
+    if (__DEV__) {
+      ReactInstrumentation.debugTool.onMountComponent(internalInstance);
+    }
     return markup;
   },
 
@@ -70,7 +74,10 @@ var ReactReconciler = {
    */
   unmountComponent: function(internalInstance, safely) {
     ReactRef.detachRefs(internalInstance, internalInstance._currentElement);
-    return internalInstance.unmountComponent(safely);
+    internalInstance.unmountComponent(safely);
+    if (__DEV__) {
+      ReactInstrumentation.debugTool.onUnmountComponent(internalInstance);
+    }
   },
 
   /**
@@ -119,6 +126,10 @@ var ReactReconciler = {
         internalInstance._currentElement.ref != null) {
       transaction.getReactMountReady().enqueue(attachRefs, internalInstance);
     }
+
+    if (__DEV__) {
+      ReactInstrumentation.debugTool.onUpdateComponent(internalInstance);
+    }
   },
 
   /**
@@ -133,6 +144,9 @@ var ReactReconciler = {
     transaction
   ) {
     internalInstance.performUpdateIfNecessary(transaction);
+    if (__DEV__) {
+      ReactInstrumentation.debugTool.onUpdateComponent(internalInstance);
+    }
   },
 
 };