diff --git a/.changeset/grumpy-years-remember.md b/.changeset/grumpy-years-remember.md
new file mode 100644
index 000000000000..1e1906cd926f
--- /dev/null
+++ b/.changeset/grumpy-years-remember.md
@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Fix, lazily initialize ResponseWithEncoding
diff --git a/packages/astro/e2e/fixtures/view-transitions/src/components/Video.astro b/packages/astro/e2e/fixtures/view-transitions/src/components/Video.astro
index 7235266bc67b..0a3a229134d1 100644
--- a/packages/astro/e2e/fixtures/view-transitions/src/components/Video.astro
+++ b/packages/astro/e2e/fixtures/view-transitions/src/components/Video.astro
@@ -1,3 +1,3 @@
-<video controls="" autoplay="" name="media" transition:persist transition:name="video">
+<video controls="" autoplay="" name="media" transition:persist transition:name="video" autoplay>
 	<source src="https://ia804502.us.archive.org/33/items/GoldenGa1939_3/GoldenGa1939_3_512kb.mp4" type="video/mp4">
 </video>
diff --git a/packages/astro/e2e/fixtures/view-transitions/src/pages/video-one.astro b/packages/astro/e2e/fixtures/view-transitions/src/pages/video-one.astro
index 76f221c630b4..a78c3c43b2c2 100644
--- a/packages/astro/e2e/fixtures/view-transitions/src/pages/video-one.astro
+++ b/packages/astro/e2e/fixtures/view-transitions/src/pages/video-one.astro
@@ -6,12 +6,4 @@ import Video from '../components/Video.astro';
 	<p id="video-one">Page 1</p>
 	<a id="click-two" href="/video-two">go to 2</a>
 	<Video />
-	<script>
-		const vid = document.querySelector('video');
-		vid.addEventListener('canplay', () => {
-			// Jump to the 1 minute mark
-			vid.currentTime = 60;
-			vid.dataset.ready = '';
-		}, { once: true });
-	</script>
 </Layout>
diff --git a/packages/astro/e2e/view-transitions.test.js b/packages/astro/e2e/view-transitions.test.js
index fc69ac64004a..12fc63e4888e 100644
--- a/packages/astro/e2e/view-transitions.test.js
+++ b/packages/astro/e2e/view-transitions.test.js
@@ -302,7 +302,7 @@ test.describe('View Transitions', () => {
 
 		// Go to page 1
 		await page.goto(astro.resolveUrl('/video-one'));
-		const vid = page.locator('video[data-ready]');
+		const vid = page.locator('video');
 		await expect(vid).toBeVisible();
 		const firstTime = await page.evaluate(getTime);
 
diff --git a/packages/astro/src/core/endpoint/index.ts b/packages/astro/src/core/endpoint/index.ts
index a6e0627270c7..b8c7000fbd32 100644
--- a/packages/astro/src/core/endpoint/index.ts
+++ b/packages/astro/src/core/endpoint/index.ts
@@ -39,6 +39,7 @@ export function createAPIContext({
 	props,
 	adapterName,
 }: CreateAPIContext): APIContext {
+	initResponseWithEncoding();
 	const context = {
 		cookies: new AstroCookies(request),
 		request,
@@ -91,27 +92,39 @@ export function createAPIContext({
 
 type ResponseParameters = ConstructorParameters<typeof Response>;
 
-export class ResponseWithEncoding extends Response {
-	constructor(body: ResponseParameters[0], init: ResponseParameters[1], encoding?: BufferEncoding) {
-		// If a body string is given, try to encode it to preserve the behaviour as simple objects.
-		// We don't do the full handling as simple objects so users can control how headers are set instead.
-		if (typeof body === 'string') {
-			// In NodeJS, we can use Buffer.from which supports all BufferEncoding
-			if (typeof Buffer !== 'undefined' && Buffer.from) {
-				body = Buffer.from(body, encoding);
+export let ResponseWithEncoding: ReturnType<typeof initResponseWithEncoding>;
+// TODO Remove this after StackBlitz supports Node 18.
+let initResponseWithEncoding = () => {
+	class LocalResponseWithEncoding extends Response {
+		constructor(body: ResponseParameters[0], init: ResponseParameters[1], encoding?: BufferEncoding) {
+			// If a body string is given, try to encode it to preserve the behaviour as simple objects.
+			// We don't do the full handling as simple objects so users can control how headers are set instead.
+			if (typeof body === 'string') {
+				// In NodeJS, we can use Buffer.from which supports all BufferEncoding
+				if (typeof Buffer !== 'undefined' && Buffer.from) {
+					body = Buffer.from(body, encoding);
+				}
+				// In non-NodeJS, use the web-standard TextEncoder for utf-8 strings
+				else if (encoding == null || encoding === 'utf8' || encoding === 'utf-8') {
+					body = encoder.encode(body);
+				}
 			}
-			// In non-NodeJS, use the web-standard TextEncoder for utf-8 strings
-			else if (encoding == null || encoding === 'utf8' || encoding === 'utf-8') {
-				body = encoder.encode(body);
+	
+			super(body, init);
+	
+			if (encoding) {
+				this.headers.set('X-Astro-Encoding', encoding);
 			}
 		}
+	}
 
-		super(body, init);
+	// Set the module scoped variable.
+	ResponseWithEncoding = LocalResponseWithEncoding;
 
-		if (encoding) {
-			this.headers.set('X-Astro-Encoding', encoding);
-		}
-	}
+	// Turn this into a noop.
+	initResponseWithEncoding = (() => {}) as any;
+
+	return LocalResponseWithEncoding;
 }
 
 export async function callEndpoint<MiddlewareResult = Response | EndpointOutput>(