diff --git a/docs/index.html b/docs/index.html
index ca71057..b36aa28 100644
--- a/docs/index.html
+++ b/docs/index.html
@@ -400,7 +400,7 @@ <h1 class="text-xl font-bold text-zinc-900 tracking-tight">✈ iframe-flight</h1
         <div class="px-4 py-3 bg-zinc-50 border-b border-zinc-200">
           <span class="text-sm font-semibold text-zinc-800">Child iframe</span>
         </div>
-        <iframe id="qs-frame" src="./child-simple.html" sandbox="allow-scripts"
+        <iframe id="qs-frame" src="about:blank" sandbox="allow-scripts"
           class="block w-full h-[200px] bg-zinc-50 border-0"></iframe>
       </div>
     </div>
@@ -487,7 +487,7 @@ <h1 class="text-xl font-bold text-zinc-900 tracking-tight">✈ iframe-flight</h1
 
   <!-- Chart iframe -->
   <div class="bg-white border border-zinc-200 rounded-lg overflow-hidden mb-4">
-    <iframe id="chart-frame" src="./child-chart.html" sandbox="allow-scripts"
+    <iframe id="chart-frame" src="about:blank" sandbox="allow-scripts"
       class="block w-full h-[460px] border-0"></iframe>
   </div>
 
@@ -580,6 +580,8 @@ <h1 class="text-xl font-bold text-zinc-900 tracking-tight">✈ iframe-flight</h1
     a.classList.toggle('text-zinc-500',  !active);
     a.classList.toggle('border-transparent', !active);
   });
+  if (page === 'simple') initQsEmitter();
+  if (page === 'chart')  initChartEmitter();
 }
 window.addEventListener('hashchange', route);
 route();
@@ -766,7 +768,7 @@ <h1 class="text-xl font-bold text-zinc-900 tracking-tight">✈ iframe-flight</h1
 q('btn-resume-alpha').addEventListener('click',()=>{ q('frame-alpha').contentWindow.postMessage({__iframeFlight:'resume'},'*'); q('btn-resume-alpha').disabled=true; appendLog('parent-log','▶ resume → child-alpha','info'); });
 q('btn-resume-beta').addEventListener('click',()=>{ q('frame-beta').contentWindow.postMessage({__iframeFlight:'resume'},'*'); q('btn-resume-beta').disabled=true; appendLog('parent-log','▶ resume → child-beta','info'); });
 
-/* ══ CHART PAGE EMITTER ══ */
+/* ══ CHART PAGE — lazy init ══ */
 const CHART_PRODUCTS = ['Aurora','Beacon','Catalyst','Dynamo','Ember','Forge','Helios','Iris','Jetstream','Kronos','Lumina','Meridian','Nexus','Orbit','Prism'];
 
 function makeChartData(n) {
@@ -777,37 +779,46 @@ <h1 class="text-xl font-bold text-zinc-900 tracking-tight">✈ iframe-flight</h1
   return tableToIPC(tableFromArrays({ product: products, revenue, growth, units }));
 }
 
-const chartRowsSlider = q('chart-rows');
-const chartRowsVal    = q('chart-rows-val');
-chartRowsSlider.addEventListener('input', () => { chartRowsVal.textContent = chartRowsSlider.value; });
-
-let chartEmitter = new ArrowParentEmitter(q('chart-frame'), { handshakeTimeout:10000, ackTimeout:6000, allowedOrigins:['*'] });
-chartEmitter
-  .onStateChange((next) => {
-    if (next === State.READY) {
-      q('chart-send').disabled = false;
-      doChartSend();
-    }
-  })
-  .onError(err => { q('chart-meta').textContent = `❌ ${err.message}`; });
+q('chart-rows').addEventListener('input', () => { q('chart-rows-val').textContent = q('chart-rows').value; });
+
+let chartEmitter = null;
+function initChartEmitter() {
+  if (chartEmitter) return;
+  q('chart-frame').src = './child-chart.html';
+  chartEmitter = new ArrowParentEmitter(q('chart-frame'), { handshakeTimeout:12000, ackTimeout:8000, allowedOrigins:['*'] });
+  chartEmitter
+    .onStateChange(next => {
+      if (next === State.READY) { q('chart-send').disabled = false; doChartSend(); }
+    })
+    .onError(err => { q('chart-meta').textContent = `❌ ${err.message}`; });
+}
 
 function doChartSend() {
-  const buf = makeChartData(parseInt(chartRowsSlider.value, 10));
+  const buf = makeChartData(parseInt(q('chart-rows').value, 10));
   const t0 = performance.now();
   chartEmitter.send(buf).then(ack => {
-    const rtt = Math.round(performance.now() - t0);
-    q('chart-meta').textContent = `${ack.rows} rows · ${ack.cols} cols · ${ack.processingTime}ms transfer · ${rtt}ms RTT`;
+    q('chart-meta').textContent = `${ack.rows} rows · ${ack.cols} cols · ${ack.processingTime}ms · RTT ${Math.round(performance.now()-t0)}ms`;
   }).catch(err => { q('chart-meta').textContent = `❌ ${err.message}`; });
 }
 
 q('chart-send').addEventListener('click', doChartSend);
 
-/* ══ QUICK START PAGE EMITTER ══ */
-let qsEmitter = new ArrowParentEmitter(q('qs-frame'), { handshakeTimeout:8000, ackTimeout:5000, allowedOrigins:['*'] });
-qsEmitter.onStateChange((next,prev) => {
-  setDot('qs-dot', null, next);
-  if (next===State.READY) { q('qs-send').disabled=false; appendLog('qs-log','✅ Ready — click send()','ok'); }
-}).onError(err => appendLog('qs-log',`❌ ${err.message}`,'err'));
+/* ══ QUICK START PAGE — lazy init ══ */
+let qsEmitter = null;
+function initQsEmitter() {
+  if (qsEmitter) return;
+  q('qs-frame').src = './child-simple.html';
+  qsEmitter = new ArrowParentEmitter(q('qs-frame'), { handshakeTimeout:10000, ackTimeout:6000, allowedOrigins:['*'] });
+  qsEmitter
+    .onStateChange((next, prev) => {
+      setDot('qs-dot', null, next);
+      if (next === State.READY && prev !== State.SENDING) {
+        q('qs-send').disabled = false;
+        appendLog('qs-log', '✅ Ready — click send()', 'ok');
+      }
+    })
+    .onError(err => appendLog('qs-log', `❌ ${err.message}`, 'err'));
+}
 
 window.addEventListener('message', e => {
   if (e.data?.__iframeFlight==='log' && e.data.sourceId==='quickstart')
@@ -816,10 +827,10 @@ <h1 class="text-xl font-bold text-zinc-900 tracking-tight">✈ iframe-flight</h1
 
 q('qs-send').addEventListener('click', () => {
   const a = makeArrowBuf();
-  appendLog('qs-log','→ send()…');
-  qsEmitter.send(a.buf,{format:'auto',schema:a.schema}).then(ack => {
-    appendLog('qs-log',`✅ rows=${ack.rows} cols=${ack.cols} zeroCopy=${ack.isZeroCopy}`,'ok');
-  }).catch(err => appendLog('qs-log',`❌ ${err.message}`,'err'));
+  appendLog('qs-log', '→ send()…');
+  qsEmitter.send(a.buf, {format:'auto', schema:a.schema}).then(ack => {
+    appendLog('qs-log', `✅ rows=${ack.rows} cols=${ack.cols} zeroCopy=${ack.isZeroCopy}`, 'ok');
+  }).catch(err => appendLog('qs-log', `❌ ${err.message}`, 'err'));
 });
 
 /* ══ TABS ══ */
diff --git a/src/ArrowParentEmitter.ts b/src/ArrowParentEmitter.ts
index 2bd69a0..edccc72 100644
--- a/src/ArrowParentEmitter.ts
+++ b/src/ArrowParentEmitter.ts
@@ -78,6 +78,12 @@ export class ArrowParentEmitter {
         return;
       }
 
+      // Reject messages not originating from our specific iframe.
+      // Without this check every ArrowParentEmitter on the page would
+      // accept the first CHILD_READY it sees, regardless of which iframe
+      // sent it, causing phantom READY transitions and ACK timeouts.
+      if (event.source !== this.iframe.contentWindow) return;
+
       if (type === MessageType.CHILD_READY) {
         if (this.handshakeTimeout) {
           clearTimeout(this.handshakeTimeout);
diff --git a/src/__tests__/ArrowParentEmitter.test.ts b/src/__tests__/ArrowParentEmitter.test.ts
index d987c4a..d8037b3 100644
--- a/src/__tests__/ArrowParentEmitter.test.ts
+++ b/src/__tests__/ArrowParentEmitter.test.ts
@@ -13,8 +13,15 @@ function makeIframe(): HTMLIFrameElement {
   return iframe;
 }
 
-function dispatchMessage(data: unknown, origin = '*') {
-  window.dispatchEvent(new MessageEvent('message', { data, origin }));
+function dispatchMessage(data: unknown, origin = '*', source?: unknown) {
+  const init: MessageEventInit = { data, origin };
+  if (source !== undefined) init.source = source as MessageEventSource;
+  window.dispatchEvent(new MessageEvent('message', init));
+}
+
+/** Dispatch a message as if it originated from this iframe's contentWindow. */
+function dispatchFromIframe(iframe: HTMLIFrameElement, data: unknown, origin = '*') {
+  dispatchMessage(data, origin, iframe.contentWindow);
 }
 
 describe('ArrowParentEmitter', () => {
@@ -46,7 +53,7 @@ describe('ArrowParentEmitter', () => {
     const readyCb = vi.fn();
     emitter = new ArrowParentEmitter(iframe).onReady(readyCb);
 
-    dispatchMessage({ type: MessageType.CHILD_READY, protocolVersion: PROTOCOL_VERSION, messageId: 'x', timestamp: Date.now(), source: 'child' });
+    dispatchFromIframe(iframe, { type: MessageType.CHILD_READY, protocolVersion: PROTOCOL_VERSION, messageId: 'x', timestamp: Date.now(), source: 'child' });
 
     expect(emitter.getState()).toBe(State.READY);
     expect(emitter.isReady()).toBe(true);
@@ -57,7 +64,7 @@ describe('ArrowParentEmitter', () => {
     emitter = new ArrowParentEmitter(iframe);
     const postMessage = iframe.contentWindow!.postMessage as ReturnType<typeof vi.fn>;
 
-    dispatchMessage({ type: MessageType.CHILD_READY, protocolVersion: PROTOCOL_VERSION, messageId: 'x', timestamp: Date.now(), source: 'child' });
+    dispatchFromIframe(iframe, { type: MessageType.CHILD_READY, protocolVersion: PROTOCOL_VERSION, messageId: 'x', timestamp: Date.now(), source: 'child' });
 
     expect(postMessage).toHaveBeenCalledWith(
       expect.objectContaining({ type: MessageType.PARENT_ACK }),
@@ -79,7 +86,7 @@ describe('ArrowParentEmitter', () => {
     const errorCb = vi.fn();
     emitter = new ArrowParentEmitter(iframe, { handshakeTimeout: 1000 }).onError(errorCb);
 
-    dispatchMessage({ type: MessageType.CHILD_READY, protocolVersion: PROTOCOL_VERSION, messageId: 'x', timestamp: Date.now(), source: 'child' });
+    dispatchFromIframe(iframe, { type: MessageType.CHILD_READY, protocolVersion: PROTOCOL_VERSION, messageId: 'x', timestamp: Date.now(), source: 'child' });
     vi.advanceTimersByTime(2000);
 
     expect(errorCb).not.toHaveBeenCalled();
@@ -89,15 +96,26 @@ describe('ArrowParentEmitter', () => {
     const readyCb = vi.fn();
     emitter = new ArrowParentEmitter(iframe, { allowedOrigins: ['https://trusted.com'] }).onReady(readyCb);
 
-    dispatchMessage({ type: MessageType.CHILD_READY, protocolVersion: PROTOCOL_VERSION }, 'https://evil.com');
+    dispatchMessage({ type: MessageType.CHILD_READY, protocolVersion: PROTOCOL_VERSION }, 'https://evil.com', iframe.contentWindow);
+    expect(readyCb).not.toHaveBeenCalled();
+  });
+
+  it('ignores CHILD_READY from a different iframe', () => {
+    const readyCb = vi.fn();
+    emitter = new ArrowParentEmitter(iframe).onReady(readyCb);
+
+    const otherIframe = makeIframe();
+    dispatchFromIframe(otherIframe, { type: MessageType.CHILD_READY, protocolVersion: PROTOCOL_VERSION, messageId: 'x', timestamp: Date.now(), source: 'child' });
+
     expect(readyCb).not.toHaveBeenCalled();
+    expect(emitter.getState()).toBe(State.CONNECTING);
   });
 
   it('fires error on protocol version mismatch', () => {
     const errorCb = vi.fn();
     emitter = new ArrowParentEmitter(iframe).onError(errorCb);
 
-    dispatchMessage({ type: MessageType.CHILD_READY, protocolVersion: '99.0.0', messageId: 'x', timestamp: Date.now(), source: 'child' });
+    dispatchFromIframe(iframe, { type: MessageType.CHILD_READY, protocolVersion: '99.0.0', messageId: 'x', timestamp: Date.now(), source: 'child' });
 
     expect(errorCb).toHaveBeenCalledWith(expect.objectContaining({ message: expect.stringContaining('version mismatch') }));
   });
@@ -111,7 +129,7 @@ describe('ArrowParentEmitter', () => {
     emitter = new ArrowParentEmitter(iframe, { ackTimeout: 3000 });
     const postMessage = iframe.contentWindow!.postMessage as ReturnType<typeof vi.fn>;
 
-    dispatchMessage({ type: MessageType.CHILD_READY, protocolVersion: PROTOCOL_VERSION, messageId: 'x', timestamp: Date.now(), source: 'child' });
+    dispatchFromIframe(iframe, { type: MessageType.CHILD_READY, protocolVersion: PROTOCOL_VERSION, messageId: 'x', timestamp: Date.now(), source: 'child' });
 
     const sendPromise = emitter.sendJSON({ hello: 'world' });
 
@@ -119,7 +137,7 @@ describe('ArrowParentEmitter', () => {
     expect(sentMsg).toBeDefined();
     expect(sentMsg!.format).toBe('json');
 
-    dispatchMessage({
+    dispatchFromIframe(iframe, {
       type: MessageType.DATA_RECEIVED,
       messageId: sentMsg!.messageId,
       success: true,
@@ -139,7 +157,7 @@ describe('ArrowParentEmitter', () => {
     emitter = new ArrowParentEmitter(iframe);
     const postMessage = iframe.contentWindow!.postMessage as ReturnType<typeof vi.fn>;
 
-    dispatchMessage({ type: MessageType.CHILD_READY, protocolVersion: PROTOCOL_VERSION, messageId: 'x', timestamp: Date.now(), source: 'child' });
+    dispatchFromIframe(iframe, { type: MessageType.CHILD_READY, protocolVersion: PROTOCOL_VERSION, messageId: 'x', timestamp: Date.now(), source: 'child' });
 
     const buf = new Uint8Array([1, 2, 3]);
     const sendPromise = emitter.sendArrowCopy(buf);
@@ -147,13 +165,13 @@ describe('ArrowParentEmitter', () => {
     const sentMsg = postMessage.mock.calls.find(([msg]) => msg.type === MessageType.DATA_TRANSFER)?.[0] as Record<string, unknown> | undefined;
     expect(sentMsg!.format).toBe('arrow-copy');
 
-    dispatchMessage({ type: MessageType.DATA_RECEIVED, messageId: sentMsg!.messageId, success: true, format: 'arrow-copy', rows: 0, cols: 0, processingTime: 1, isZeroCopy: false });
+    dispatchFromIframe(iframe, { type: MessageType.DATA_RECEIVED, messageId: sentMsg!.messageId, success: true, format: 'arrow-copy', rows: 0, cols: 0, processingTime: 1, isZeroCopy: false });
     await sendPromise;
   });
 
   it('ACK timeout rejects the send promise', async () => {
     emitter = new ArrowParentEmitter(iframe, { ackTimeout: 500 });
-    dispatchMessage({ type: MessageType.CHILD_READY, protocolVersion: PROTOCOL_VERSION, messageId: 'x', timestamp: Date.now(), source: 'child' });
+    dispatchFromIframe(iframe, { type: MessageType.CHILD_READY, protocolVersion: PROTOCOL_VERSION, messageId: 'x', timestamp: Date.now(), source: 'child' });
 
     const sendPromise = emitter.sendJSON({ data: 'x' });
     vi.advanceTimersByTime(600);
@@ -163,7 +181,7 @@ describe('ArrowParentEmitter', () => {
 
   it('close rejects pending ACKs', async () => {
     emitter = new ArrowParentEmitter(iframe);
-    dispatchMessage({ type: MessageType.CHILD_READY, protocolVersion: PROTOCOL_VERSION, messageId: 'x', timestamp: Date.now(), source: 'child' });
+    dispatchFromIframe(iframe, { type: MessageType.CHILD_READY, protocolVersion: PROTOCOL_VERSION, messageId: 'x', timestamp: Date.now(), source: 'child' });
 
     const sendPromise = emitter.sendJSON({ data: 'x' });
     emitter.close();
@@ -176,7 +194,7 @@ describe('ArrowParentEmitter', () => {
     const cb = vi.fn();
     emitter = new ArrowParentEmitter(iframe).onStateChange(cb);
 
-    dispatchMessage({ type: MessageType.CHILD_READY, protocolVersion: PROTOCOL_VERSION, messageId: 'x', timestamp: Date.now(), source: 'child' });
+    dispatchFromIframe(iframe, { type: MessageType.CHILD_READY, protocolVersion: PROTOCOL_VERSION, messageId: 'x', timestamp: Date.now(), source: 'child' });
 
     expect(cb).toHaveBeenCalledWith(State.READY, State.CONNECTING);
   });
@@ -185,19 +203,19 @@ describe('ArrowParentEmitter', () => {
     emitter = new ArrowParentEmitter(iframe);
     const postMessage = iframe.contentWindow!.postMessage as ReturnType<typeof vi.fn>;
 
-    dispatchMessage({ type: MessageType.CHILD_READY, protocolVersion: PROTOCOL_VERSION, messageId: 'x', timestamp: Date.now(), source: 'child' });
+    dispatchFromIframe(iframe, { type: MessageType.CHILD_READY, protocolVersion: PROTOCOL_VERSION, messageId: 'x', timestamp: Date.now(), source: 'child' });
 
     const sendPromise = emitter.send([{ id: 1 }]);
     const sentMsg = postMessage.mock.calls.find(([msg]) => msg.type === MessageType.DATA_TRANSFER)?.[0] as Record<string, unknown>;
     expect(sentMsg.format).toBe('json');
 
-    dispatchMessage({ type: MessageType.DATA_RECEIVED, messageId: sentMsg.messageId, success: true, format: 'json', rows: 1, cols: 1, processingTime: 1, isZeroCopy: false });
+    dispatchFromIframe(iframe, { type: MessageType.DATA_RECEIVED, messageId: sentMsg.messageId, success: true, format: 'json', rows: 1, cols: 1, processingTime: 1, isZeroCopy: false });
     await sendPromise;
   });
 
   it('send() throws on unknown format', async () => {
     emitter = new ArrowParentEmitter(iframe);
-    dispatchMessage({ type: MessageType.CHILD_READY, protocolVersion: PROTOCOL_VERSION, messageId: 'x', timestamp: Date.now(), source: 'child' });
+    dispatchFromIframe(iframe, { type: MessageType.CHILD_READY, protocolVersion: PROTOCOL_VERSION, messageId: 'x', timestamp: Date.now(), source: 'child' });
 
     await expect(emitter.send({}, { format: 'xml' as never })).rejects.toThrow('Unknown format');
   });