sveltejs · Rich-Harris · Jul 30, 2026 · Jul 29, 2026 · Jul 30, 2026
diff --git a/.changeset/adapter-node-manifest-mime-types.md b/.changeset/adapter-node-manifest-mime-types.md
@@ -0,0 +1,5 @@
+---
+'@sveltejs/adapter-node': patch
+---
+
+fix: serve static files with the Content-Type recorded in the manifest
diff --git a/.changeset/kit-prerendered-mime-types.md b/.changeset/kit-prerendered-mime-types.md
@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+fix: record the mime types of prerendered paths in the server manifest
diff --git a/packages/adapter-node/src/handler.js b/packages/adapter-node/src/handler.js
@@ -45,17 +45,21 @@ function serve(path, client = false) {
 				etag: true,
 				gzip: PRECOMPRESS,
 				brotli: PRECOMPRESS,
-				setHeaders: client
-					? (res, pathname) => {
-							// only apply to build directory, not e.g. version.json
-							if (
-								pathname.startsWith(`/${manifest.appPath}/immutable/`) &&
-								res.statusCode === 200
-							) {
-								res.setHeader('cache-control', 'public,max-age=31536000,immutable');
-							}
-						}
-					: undefined
+				setHeaders: (res, pathname) => {
+					// `sirv` uses its own bundled `mrmime`, which the manifest's added types never reach
+					let type = manifest.mimeTypes[pathname.slice(pathname.lastIndexOf('.'))];
+					if (type === 'text/html') type += ';charset=utf-8';
+					if (type) res.setHeader('content-type', type);
+
+					// only apply to build directory, not e.g. version.json
+					if (
+						client &&
+						pathname.startsWith(`/${manifest.appPath}/immutable/`) &&
+						res.statusCode === 200
+					) {
+						res.setHeader('cache-control', 'public,max-age=31536000,immutable');
+					}
+				}
 			})
 		: undefined;
 }

diff --git a/packages/adapter-node/test/apps/basic/src/routes/prerendered.ico/+server.js b/packages/adapter-node/test/apps/basic/src/routes/prerendered.ico/+server.js
@@ -0,0 +1,7 @@
+export const prerender = true;
+
+export function GET() {
+	return new Response(new Uint8Array([0, 0, 1, 0]), {
+		headers: { 'content-type': 'image/x-icon' }
+	});
+}
diff --git a/packages/adapter-node/test/apps/basic/static/page.html b/packages/adapter-node/test/apps/basic/static/page.html
@@ -0,0 +1,2 @@
+<!doctype html>
+<p>hi</p>
diff --git a/packages/adapter-node/test/apps/basic/static/test.ico b/packages/adapter-node/test/apps/basic/static/test.ico
diff --git a/packages/adapter-node/test/apps/basic/test/test.js b/packages/adapter-node/test/apps/basic/test/test.js
@@ -22,3 +22,24 @@ test('does not set X-Accel-Buffering header on other responses', async ({ reques
 	const response = await request.get('/');
 	expect(response.headers()['x-accel-buffering']).toBeUndefined();
 });
+
+test('serves static files with the Content-Type from the manifest', async ({ request }) => {
+	// https://github.com/sveltejs/kit/issues/13753
+	const response = await request.get('/test.ico');
+	expect(response.status()).toBe(200);
+	expect(response.headers()['content-type']).toBe('image/x-icon');
+});
+
+test('serves prerendered endpoints with the Content-Type from the manifest', async ({
+	request
+}) => {
+	const response = await request.get('/prerendered.ico');
+	expect(response.status()).toBe(200);
+	expect(response.headers()['content-type']).toBe('image/x-icon');
+});
+
+test('serves static HTML with a charset', async ({ request }) => {
+	const response = await request.get('/page.html');
+	expect(response.status()).toBe(200);
+	expect(response.headers()['content-type']).toBe('text/html;charset=utf-8');
+});
diff --git a/packages/kit/src/core/generate_manifest/index.js b/packages/kit/src/core/generate_manifest/index.js
@@ -94,6 +94,12 @@ export function generate_manifest({
 		mime_types[ext] ??= mime_lookup(ext) || '';
 	}
 
+	// record extensions that only exist in prerendered output, e.g. a prerendered favicon.ico
+	for (const pathname of prerendered) {
+		const ext = path.extname(pathname);
+		if (ext) mime_types[ext] ??= mime_lookup(ext) || '';
+	}
+
 	// prettier-ignore
 	// String representation of
 	/** @template {import('@sveltejs/kit').SSRManifest} T */