diff --git a/src/renderers/noop/ReactNoop.js b/src/renderers/noop/ReactNoop.js
index 9214a1865b..4ffa0b6582 100644
--- a/src/renderers/noop/ReactNoop.js
+++ b/src/renderers/noop/ReactNoop.js
@@ -20,20 +20,44 @@
 'use strict';
 
 import type { Fiber } from 'ReactFiber';
+import type { HostChildren } from 'ReactFiberReconciler';
 
 var ReactFiberReconciler = require('ReactFiberReconciler');
 
 var scheduledHighPriCallback = null;
 var scheduledLowPriCallback = null;
 
+type Props = { };
+type Instance = { id: number };
+
+var instanceCounter = 0;
+
 var NoopRenderer = ReactFiberReconciler({
 
-  createHostInstance() {
-
+  createInstance(type : string, props : Props, children : HostChildren<Instance>) : Instance {
+    console.log('Create instance #' + instanceCounter);
+    return {
+      id: instanceCounter++
+    };
   },
+
+  prepareUpdate(instance : Instance, oldProps : Props, newProps : Props, children : HostChildren<Instance>) : boolean {
+    console.log('Prepare for update on #' + instance.id);
+    return true;
+  },
+
+  commitUpdate(instance : Instance, oldProps : Props, newProps : Props, children : HostChildren<Instance>) : void {
+    console.log('Commit update on #' + instance.id);
+  },
+
+  deleteInstance(instance : Instance) : void {
+    console.log('Delete #' + instance.id);
+  },
+
   scheduleHighPriCallback(callback) {
     scheduledHighPriCallback = callback;
   },
+
   scheduleLowPriCallback(callback) {
     scheduledLowPriCallback = callback;
   },
diff --git a/src/renderers/shared/fiber/ReactFiber.js b/src/renderers/shared/fiber/ReactFiber.js
index b4dbb18880..39683f001e 100644
--- a/src/renderers/shared/fiber/ReactFiber.js
+++ b/src/renderers/shared/fiber/ReactFiber.js
@@ -48,7 +48,7 @@ type Instance = {
   type: any,
 
   // The local state associated with this fiber.
-  stateNode: ?Object,
+  stateNode: any,
 
   // Conceptual aliases
   // parent : Instance -> return The parent happens to be the same as the
diff --git a/src/renderers/shared/fiber/ReactFiberCommitWork.js b/src/renderers/shared/fiber/ReactFiberCommitWork.js
index 161c2b3c8d..1f3e5e5a22 100644
--- a/src/renderers/shared/fiber/ReactFiberCommitWork.js
+++ b/src/renderers/shared/fiber/ReactFiberCommitWork.js
@@ -24,6 +24,8 @@ var {
 
 module.exports = function<T, P, I>(config : HostConfig<T, P, I>) {
 
+  const commitUpdate = config.commitUpdate;
+
   function commitWork(finishedWork : Fiber) : void {
     switch (finishedWork.tag) {
       case ClassComponent:
@@ -33,7 +35,17 @@ module.exports = function<T, P, I>(config : HostConfig<T, P, I>) {
         // TODO: Attach children to root container.
         return;
       case HostComponent:
-        console.log('commit updates to host component', finishedWork.type);
+        if (finishedWork.stateNode == null || !finishedWork.alternate) {
+          throw new Error('This should only be done during updates.');
+        }
+        const children = finishedWork.output;
+        const newProps = finishedWork.memoizedProps;
+        // If we have an alternate, that means this is an update and we need to
+        // schedule a side-effect to do the updates.
+        const current = finishedWork.alternate;
+        const oldProps = current.memoizedProps;
+        const instance : I = finishedWork.stateNode;
+        commitUpdate(instance, oldProps, newProps, children);
         return;
       default:
         throw new Error('This unit of work tag should not have side-effects.');
diff --git a/src/renderers/shared/fiber/ReactFiberCompleteWork.js b/src/renderers/shared/fiber/ReactFiberCompleteWork.js
index 50c6e6895f..6f4752ccc0 100644
--- a/src/renderers/shared/fiber/ReactFiberCompleteWork.js
+++ b/src/renderers/shared/fiber/ReactFiberCompleteWork.js
@@ -15,7 +15,6 @@
 import type { ReactCoroutine } from 'ReactCoroutine';
 import type { Fiber } from 'ReactFiber';
 import type { HostConfig } from 'ReactFiberReconciler';
-
 import type { ReifiedYield } from 'ReactReifiedYield';
 
 var ReactChildFiber = require('ReactChildFiber');
@@ -33,6 +32,9 @@ var {
 
 module.exports = function<T, P, I>(config : HostConfig<T, P, I>) {
 
+  const createInstance = config.createInstance;
+  const prepareUpdate = config.prepareUpdate;
+
   function markForPostEffect(workInProgress : Fiber) {
     // Schedule a side-effect on this fiber, after the children's side-effects.
     if (workInProgress.lastEffect) {
@@ -120,13 +122,24 @@ module.exports = function<T, P, I>(config : HostConfig<T, P, I>) {
       case HostContainer:
         return null;
       case HostComponent:
+        console.log('/host component', workInProgress.type);
         transferOutput(workInProgress.child, workInProgress);
-        if (workInProgress.alternate) {
+        const children = workInProgress.output;
+        const newProps = workInProgress.memoizedProps;
+        if (workInProgress.alternate && workInProgress.stateNode != null) {
           // If we have an alternate, that means this is an update and we need to
           // schedule a side-effect to do the updates.
-          markForPostEffect(workInProgress);
+          const current = workInProgress.alternate;
+          const oldProps = current.memoizedProps;
+          const instance : I = workInProgress.stateNode;
+          if (prepareUpdate(instance, oldProps, newProps, children)) {
+            // This returns true if there was something to update.
+            markForPostEffect(workInProgress);
+          }
+        } else {
+          const instance = createInstance(workInProgress.type, newProps, children);
+          workInProgress.stateNode = instance;
         }
-        console.log('/host component', workInProgress.type);
         return null;
       case CoroutineComponent:
         console.log('/coroutine component', workInProgress.pendingProps.handler.name);
diff --git a/src/renderers/shared/fiber/ReactFiberReconciler.js b/src/renderers/shared/fiber/ReactFiberReconciler.js
index 3fde615cf0..28421314ab 100644
--- a/src/renderers/shared/fiber/ReactFiberReconciler.js
+++ b/src/renderers/shared/fiber/ReactFiberReconciler.js
@@ -22,18 +22,21 @@ var {
   LowPriority,
 } = require('ReactPriorityLevel');
 
-type ReactHostElement<T, P> = {
-  type: T,
-  props: P
-};
-
 type Deadline = {
   timeRemaining : () => number
 };
 
+type HostChildNode<I> = { output: HostChildren<I>, sibling: ?HostChildNode<I> };
+
+export type HostChildren<I> = null | void | I | HostChildNode<I>;
+
 export type HostConfig<T, P, I> = {
 
-  createHostInstance(element : ReactHostElement<T, P>) : I,
+  createInstance(type : T, props : P, children : HostChildren<I>) : I,
+  prepareUpdate(instance : I, oldProps : P, newProps : P, children : HostChildren<I>) : bool,
+  commitUpdate(instance : I, oldProps : P, newProps : P, children : HostChildren<I>) : void,
+  deleteInstance(instance : I) : void,
+
   scheduleHighPriCallback(callback : () => void) : void,
   scheduleLowPriCallback(callback : (deadline : Deadline) => void) : void