diff --git a/CHANGELOG.md b/CHANGELOG.md
index 19c4da8a..19ecb8bd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,8 @@ See [Conventional Commits](https://conventionalcommits.org) for commit guideline
 ### Added
 
 * **client-api-react**: Add `pointStrokeWidth` and `showCollections` bindings
+* **client-api**: Add `playUpdates` observer which creates event when graph simulation completes
+* **client-api-react**: Add `onPlayComplete` callback property
 
 ### Security
 
diff --git a/projects/client-api-react/src/index.js b/projects/client-api-react/src/index.js
index 9d430cdd..bb6075bb 100644
--- a/projects/client-api-react/src/index.js
+++ b/projects/client-api-react/src/index.js
@@ -9,7 +9,7 @@ import * as gAPI from '@graphistry/client-api';
 import { ajax, catchError, first, forkJoin, map, of, switchMap, tap } from '@graphistry/client-api';  // avoid explicit rxjs dep
 import { bg } from './bg';
 import { bindings, panelNames, calls } from './bindings.js';
-import { Client as ClientBase, ClientPKey as ClientPKeyBase, selectionUpdates, subscribeLabels } from '@graphistry/client-api';
+import { Client as ClientBase, ClientPKey as ClientPKeyBase, selectionUpdates, subscribeLabels, playUpdates } from '@graphistry/client-api';
 
 export const Client = ClientBase;
 export const ClientPKey = ClientPKeyBase;
@@ -104,6 +104,7 @@ const propTypes = {
     onUpdateObservableG: PropTypes.func,
     onSelectionUpdate: PropTypes.func,
     onLabelsUpdate: PropTypes.func,
+    onPlayComplete: PropTypes.func,
     selectionUpdateOptions: PropTypes.object,
 
     queryParamExtra: PropTypes.object
@@ -467,6 +468,7 @@ const Graphistry = forwardRef((props, ref) => {
         onUpdateObservableG,
         onSelectionUpdate,
         onLabelsUpdate,
+        onPlayComplete,
         selectionUpdateOptions
     } = props;
 
@@ -558,6 +560,20 @@ const Graphistry = forwardRef((props, ref) => {
         }
     }, [g, onLabelsUpdate])
 
+    useEffect(() => {
+        if (g && onPlayComplete) {
+            const sub = playUpdates(g)
+                .subscribe(
+                    (v) => onPlayComplete(undefined, v),
+                    (error) => onPlayComplete(error)
+                );
+
+            return () => {
+                sub && sub.unsubscribe();
+            };
+        }
+    }, [g, onPlayComplete])
+
     const playNormalized = typeof play === 'boolean' ? play : (play | 0) * 1000;
     const optionalParams = (type ? `&type=${type}` : ``) +
         (controls ? `&controls=${controls}` : ``) +
diff --git a/projects/client-api-react/src/stories/Graphistry.stories.jsx b/projects/client-api-react/src/stories/Graphistry.stories.jsx
index 70d41620..77e6dc95 100644
--- a/projects/client-api-react/src/stories/Graphistry.stories.jsx
+++ b/projects/client-api-react/src/stories/Graphistry.stories.jsx
@@ -97,6 +97,24 @@ export const OnLabelUpdate = {
   },
 };
 
+export const OnPlayUpdate = {
+  render: (args) => {
+    const [numPlayComplete, setNumPlayComplete] = useState(0);
+
+    const onPlayUpdate = () => {
+      console.log('onLabelsUpdate');
+      setNumPlayComplete(numPlayComplete + 1);
+    };
+
+    return (
+      <div>
+        {`Number of play completed: ${numPlayComplete}`}
+        <Graphistry {...defaultSettings} {...args} onPlayUpdate={onPlayUpdate} />
+      </div>
+    );
+  },
+};
+
 export const NoClusteringOnLoad = {
   render: (args) => <Graphistry {...defaultSettings} {...args} play={0} />,
 };
diff --git a/projects/client-api/src/index.js b/projects/client-api/src/index.js
index 1f41114b..aa988c4d 100644
--- a/projects/client-api/src/index.js
+++ b/projects/client-api/src/index.js
@@ -133,6 +133,7 @@ import {
     mergeAll,
     Observable,
     of,
+    pairwise,
     pipe,
     ReplaySubject,
     BehaviorSubject,
@@ -1510,7 +1511,7 @@ export function subscribeSelections({ onChange, g }) {
  * The inner {@link Observable} for a label will complete if the label is removed from the screen.
  * </p><p>
  * @function labelUpdates
- * @param {@link GraphistryState} [g] A {@link GraphistryState} {@link Observable} or depricated, cache an object.
+ * @param {@link GraphistryState} [g] A {@link GraphistryState} {@link Observable} or deprecated, cache an object.
  * @return {Observable<Observable<LabelEvent>>} An {@link Observable} of inner {Observables}, where each
  * inner {@link Observable} represents the lifetime of a label in the visualization.
  * @example
@@ -1670,6 +1671,48 @@ export function subscribeLabels({ onChange, onExit, onError, g }) {
         .subscribe({ error: onError });
 }
 
+/**
+ * Subscribe to graph simulation completion event
+ * @function playUpdates
+ * @param {@link GraphistryState} [g] A {@link GraphistryState} {@link Observable}
+ * @return {Subscription} A {@link Subscription} that can be used to react to the play updates
+ * @example
+ * GraphistryJS(document.getElementById('viz'))
+ *     .pipe(
+ *          map(playUpdates),
+ *          tap(() => console.log('Play completed')),
+ *     })
+ *     .subscribe();
+ */
+export function playUpdates(g) {
+    if (!(g.subscriptionAPIVersion >= 1)) {
+        return throwError(() => new Error('playUpdates is not available the currently embedded graphistry viz.'));
+    }
+
+    const selectionPath = ".labels";
+    return (new BehaviorSubject('Initialize playUpdates stream')
+        .pipe(
+            tap(() => {
+                console.debug('postMessage subscription', '@client-api.playUpdate');
+                g.iFrame.contentWindow.postMessage({ type: 'graphistry-subscribe', agent: 'graphistryjs', path: selectionPath }, '*');
+            }),
+            finalize(() => {
+                console.debug('postMessage unsubscribe', '@client-api.playUpdate');
+                g.iFrame.contentWindow.postMessage({ type: 'graphistry-unsubscribe', agent: 'graphistryjs', path: selectionPath }, '*');
+            }),
+            switchMap(() =>
+                fromEvent(window, 'message').pipe(
+                    map(o => o.data),
+                    filter(o => o && o.type === 'graphistry-sub-update' && o.path === selectionPath),
+                    map(o => o.data),
+                    pairwise(),
+                    filter(([{ simulating: prevSim }, { simulating: currSim }]) => prevSim && !currSim),
+                    shareReplay({ bufferSize: 1, refCount: true })
+                ),
+            )
+        ));
+}
+
 class GraphistryState {
 
     constructor(subscriptionAPIVersion, iFrame, models, result) {
@@ -1768,7 +1811,7 @@ function addCallbacks(obs, target) {
     target.labelUpdates = labelUpdates;// lift(obs, labelUpdates);
     target.subscribeLabels = subscribeLabels;//lift(obs, subscribeLabels);
     target.selectionUpdates = selectionUpdates; // lift(obs, selectionUpdates);
-    target.subscribeLabels
+    target.playUpdates = playUpdates;
     return target;
 }
 
diff --git a/projects/client-api/src/rxjs.js b/projects/client-api/src/rxjs.js
index 952444fe..7a86efc2 100644
--- a/projects/client-api/src/rxjs.js
+++ b/projects/client-api/src/rxjs.js
@@ -28,6 +28,7 @@ import {
     map,
     mergeMap,
     mergeAll,
+    pairwise,
     scan,
     share,
     shareReplay,
@@ -58,6 +59,7 @@ export {
     mergeAll,
     Observable,
     of,
+    pairwise,
     pipe,
     ReplaySubject,
     retryWhen,