code · pull · May 1, 2026 · Apr 30, 2026 · Apr 30, 2026
diff --git a/apps/router-e2e/__e2e__/static-rendering/app/metadata-async/[id].tsx b/apps/router-e2e/__e2e__/static-rendering/app/metadata-async/[id].tsx
@@ -0,0 +1,15 @@
+import type { GenerateMetadataFunction, Metadata } from 'expo-router/server';
+import { Text } from 'react-native';
+
+export const generateMetadata: GenerateMetadataFunction = async (request, params) => {
+  const pathname = new URL(request.url).pathname;
+
+  return {
+    title: `Async Metadata ${params.id}`,
+    description: `Async metadata for ${pathname}`,
+  } satisfies Metadata;
+};
+
+export default function AsyncMetadataPage() {
+  return <Text testID="async-metadata-text">Async Metadata</Text>;
+}
diff --git a/apps/router-e2e/__e2e__/static-rendering/app/metadata.tsx b/apps/router-e2e/__e2e__/static-rendering/app/metadata.tsx
@@ -0,0 +1,31 @@
+import Head from 'expo-router/head';
+import { Text } from 'react-native';
+import type { GenerateMetadataFunction, Metadata } from 'expo-router/server';
+
+export const generateMetadata: GenerateMetadataFunction = async () => {
+  return {
+    title: 'Metadata Page',
+    description: 'Page with generateMetadata',
+    keywords: ['metadata', 'e2e'],
+    openGraph: {
+      title: 'Metadata OG Title',
+      description: 'Metadata OG Description',
+    },
+    twitter: {
+      card: 'summary',
+      title: 'Metadata Twitter Title',
+    },
+  } satisfies Metadata;
+};
+
+export default function MetadataPage() {
+  return (
+    <>
+      {/* The <Head> component is here to check that the app doesn't crash when using it with `generateMetadata()` */}
+      <Head>
+        <meta name="expo-e2e-metadata-head" content="head" />
+      </Head>
+      <Text testID="metadata-text">Metadata</Text>
+    </>
+  );
+}
diff --git a/packages/@expo/cli/CHANGELOG.md b/packages/@expo/cli/CHANGELOG.md
@@ -15,6 +15,8 @@
 - Enable parallel CocoaPods code signing to speed up device builds. ([#43529](https://github.com/expo/expo/pull/43529) by [@evanbacon](https://github.com/evanbacon))
 - Prompt before clearing native folders when we detect project as a native module ([#44458](https://github.com/expo/expo/pull/44458) by [@kitten](https://github.com/kitten))
 - Rewrite @react-navigation/core to expo-router for library compatibility ([#45039](https://github.com/expo/expo/pull/45039) by [@Ubax](https://github.com/Ubax))
+- Use stream rendering in SSR ([#43963](https://github.com/expo/expo/pull/43963) by [@hassankhan](https://github.com/hassankhan))
+- Add support for metadata in streaming SSR ([#44731](https://github.com/expo/expo/pull/44731) by [@hassankhan](https://github.com/hassankhan))
 
 ### 🐛 Bug fixes
 

diff --git a/packages/@expo/cli/e2e/__tests__/export/__snapshots__/server-rendering.test.ts.snap b/packages/@expo/cli/e2e/__tests__/export/__snapshots__/server-rendering.test.ts.snap
diff --git a/packages/@expo/cli/e2e/__tests__/export/server-rendering.test.ts b/packages/@expo/cli/e2e/__tests__/export/server-rendering.test.ts
@@ -34,6 +34,11 @@ describe('exports server', () => {
   )('$name requests', (config) => {
     const server = setupServer(config);
 
+    it('sets the `Transfer-Encoding: chunked` header', async () => {
+      const res = await server.fetchAsync('/');
+      expect(res.headers.get('Transfer-Encoding')).toEqual('chunked');
+    });
+
     it(`can serve up index html`, async () => {
       const html = getHtml(await server.fetchAsync('/').then((res) => res.text()));
       expect(html.querySelector('[data-testid="index-text"]')?.textContent).toEqual('Index');
@@ -214,7 +219,25 @@ describe('exports server', () => {
     it('injects hydration assets into SSR response', async () => {
       const html = await server.fetchAsync('/').then((res) => res.text());
 
-      expect(html).toMatch(/<script src="\/_expo\/static\/js\/web\/entry-.*\.js" defer><\/script>/);
+      // Streaming SSR uses bootstrapScripts which emits async scripts (with an id attribute)
+      expect(html).toMatch(
+        /<script src="\/_expo\/static\/js\/web\/entry-.*\.js"[^>]*async=""><\/script>/
+      );
+    });
+
+    it('emits the hydration flag before the bootstrap script', async () => {
+      const html = await server.fetchAsync('/').then((res) => res.text());
+
+      const hydrationFlagIndex = html.indexOf(
+        '<script type="module">globalThis.__EXPO_ROUTER_HYDRATE__=true;</script>'
+      );
+      const bootstrapScriptIndex = html.search(
+        /<script src="\/_expo\/static\/js\/web\/entry-.*\.js"[^>]*async=""><\/script>/
+      );
+
+      expect(hydrationFlagIndex).toBeGreaterThanOrEqual(0);
+      expect(bootstrapScriptIndex).toBeGreaterThanOrEqual(0);
+      expect(hydrationFlagIndex).toBeLessThan(bootstrapScriptIndex);
     });
 
     it('SSR styles are injected', async () => {
@@ -242,7 +265,10 @@ describe('exports server', () => {
 
       const links = indexHtml.querySelectorAll('html > head > link').filter((link) => {
         // Fonts are tested elsewhere
-        return link.attributes.as !== 'font';
+        if (link.attributes.as === 'font') return false;
+        // Streaming SSR adds <link rel="preload" as="script"> for bootstrapScripts
+        if (link.attributes.as === 'script') return false;
+        return true;
       });
       expect(links.length).toBe(
         // Global CSS, CSS Module
@@ -284,7 +310,10 @@ describe('exports server', () => {
 
       // CSS Module
       expect(
-        fs.readFileSync(path.join(server.outputDir, 'client', links[2]?.attributes.href ?? ''), 'utf-8')
+        fs.readFileSync(
+          path.join(server.outputDir, 'client', links[2]?.attributes.href ?? ''),
+          'utf-8'
+        )
       ).toMatchInlineSnapshot(`".HPV33q_text{color:#1e90ff}"`);
 
       const styledHtml = getHtml(await server.fetchAsync('/styled').then((res) => res.text()));
@@ -310,7 +339,11 @@ describe('exports server', () => {
 
       expect(
         fs.readFileSync(
-          path.join(server.outputDir, 'client', links[0]?.attributes.href?.replace(/\?.*$/, '') ?? ''),
+          path.join(
+            server.outputDir,
+            'client',
+            links[0]?.attributes.href?.replace(/\?.*$/, '') ?? ''
+          ),
           'utf-8'
         )
       ).toBeDefined();
@@ -340,10 +373,33 @@ describe('exports server', () => {
       // Root element
       expect(page).toContain('<div id="root">');
 
-      const sanitized = page.replace(
-        /<script src="\/_expo\/static\/js\/web\/.*" defer>/,
-        '<script src="/_expo/static/js/web/[mock].js" defer>'
-      );
+      const sanitized = page
+        // Streaming SSR: <script src="..." id="_R_" async="">
+        .replace(
+          /<script src="\/_expo\/static\/js\/web\/[^"]*"[^>]*async="">/,
+          '<script src="/_expo/static/js/web/[mock].js" async="">'
+        )
+        // Streaming SSR: <link rel="preload" as="script" fetchPriority="low" href="..."/>
+        .replace(
+          /<link rel="preload" as="script"[^>]*href="\/_expo\/static\/js\/web\/[^"]*"[^>]*\/>/,
+          '<link rel="preload" as="script" href="/_expo/static/js/web/[mock].js"/>'
+        )
+        .replace(
+          /<link rel="preload" href="\/_expo\/static\/css\/global-[^"]*\.css" as="style">/,
+          '<link rel="preload" href="/_expo/static/css/global-[mock].css" as="style">'
+        )
+        .replace(
+          /<link rel="stylesheet" href="\/_expo\/static\/css\/global-[^"]*\.css">/,
+          '<link rel="stylesheet" href="/_expo/static/css/global-[mock].css">'
+        )
+        .replace(
+          /<link rel="preload" href="\/_expo\/static\/css\/test\.module-[^"]*\.css" as="style">/,
+          '<link rel="preload" href="/_expo/static/css/test.module-[mock].css" as="style">'
+        )
+        .replace(
+          /<link rel="stylesheet" href="\/_expo\/static\/css\/test\.module-[^"]*\.css">/,
+          '<link rel="stylesheet" href="/_expo/static/css/test.module-[mock].css">'
+        );
       expect(sanitized).toMatchSnapshot();
 
       expect(
@@ -388,5 +444,38 @@ describe('exports server', () => {
         ).querySelector('html > head > meta[name="expo-nested-layout"]')?.attributes.content
       ).toBe('TEST_VALUE');
     });
+
+    it('injects `generateMetadata()` result into the initial server HTML <head>', async () => {
+      const html = await server.fetchAsync('/metadata').then((res) => res.text());
+      const page = getHtml(html);
+      const head = page.querySelector('html > head');
+
+      expect(page.querySelector('html > body [data-testid="metadata-text"]')?.innerText).toBe(
+        'Metadata'
+      );
+      expect(head).not.toBeNull();
+
+      const metadataHeadNodes = head!.childNodes
+        .filter(
+          (node: any) => node.rawTagName && ['title', 'meta'].includes(node.rawTagName as string)
+        )
+        .map((node) => node.toString());
+
+      expect(metadataHeadNodes).toMatchSnapshot();
+    });
+
+    it('resolves async `generateMetadata()` with request and route params', async () => {
+      const page = getHtml(
+        await server.fetchAsync('/metadata-async/123').then((res) => res.text())
+      );
+
+      expect(page.querySelector('html > body [data-testid="async-metadata-text"]')?.innerText).toBe(
+        'Async Metadata'
+      );
+      expect(page.querySelector('html > head > title')?.innerText).toBe('Async Metadata 123');
+      expect(page.querySelector('html > head > meta[name="description"]')?.attributes.content).toBe(
+        'Async metadata for /metadata-async/123'
+      );
+    });
   });
 });
diff --git a/packages/@expo/cli/e2e/__tests__/export/static-splitting.test.ts b/packages/@expo/cli/e2e/__tests__/export/static-splitting.test.ts
@@ -101,6 +101,8 @@ describe('exports static with bundle splitting', () => {
         'asset',
         'links',
         'styled',
+        'metadata',
+        '\\[id\\]',
       ]
         .sort()
         .map((file) =>
@@ -114,8 +116,8 @@ describe('exports static with bundle splitting', () => {
       expect(sourceMap.version).toBe(3);
 
       // Common chunk
-      if (file!.match(/head/)) {
-        expect(sourceMap.sources.length).toEqual(29);
+      if (file!.match(/__common/)) {
+        expect(sourceMap.sources.length).toEqual(43);
       } else {
         // expect(sourceMap.sources).toEqual(
         //   expect.arrayContaining([
@@ -155,9 +157,7 @@ describe('exports static with bundle splitting', () => {
     // non-public env vars are injected during SSG
     expect(queryMeta('expo-e2e-private-env-var-client')).toEqual('not-public-value');
 
-    const script = indexHtml
-      .querySelectorAll('script')
-      .find((script) => !!script.attributes.src);
+    const script = indexHtml.querySelectorAll('script').find((script) => !!script.attributes.src);
     const jsBundle = fs.readFileSync(path.join(outputDir, script?.attributes.src ?? ''), 'utf8');
 
     // Ensure the bundle is valid
@@ -255,7 +255,10 @@ describe('exports static with bundle splitting', () => {
     );
 
     expect(
-      fs.readFileSync(path.join(outputDir, links[0]?.attributes.href?.replace(/\?.*$/, '') ?? ''), 'utf-8')
+      fs.readFileSync(
+        path.join(outputDir, links[0]?.attributes.href?.replace(/\?.*$/, '') ?? ''),
+        'utf-8'
+      )
     ).toBeDefined();
 
     // Ensure the font is used

diff --git a/packages/@expo/cli/e2e/playwright/prod/server-rendering.test.ts b/packages/@expo/cli/e2e/playwright/prod/server-rendering.test.ts
@@ -0,0 +1,74 @@
+import { test, expect } from '@playwright/test';
+
+import { clearEnv, restoreEnv } from '../../__tests__/export/export-side-effects';
+import { getRouterE2ERoot } from '../../__tests__/utils';
+import { createExpoServe, executeExpoAsync } from '../../utils/expo';
+import { pageCollectErrors } from '../page';
+
+test.beforeAll(() => clearEnv());
+test.afterAll(() => restoreEnv());
+
+const projectRoot = getRouterE2ERoot();
+const outputDir = 'dist-server-rendering-async-playwright';
+
+test.describe('server rendering in production', () => {
+  const expoServe = createExpoServe({
+    cwd: projectRoot,
+    env: {
+      NODE_ENV: 'production',
+      TEST_SECRET_KEY: 'test-secret-key',
+    },
+  });
+
+  test.beforeAll(async () => {
+    console.time('expo export');
+    await executeExpoAsync(projectRoot, ['export', '-p', 'web', '--output-dir', outputDir], {
+      env: {
+        NODE_ENV: 'production',
+        EXPO_USE_STATIC: 'server',
+        E2E_ROUTER_SRC: 'static-rendering',
+        E2E_ROUTER_SERVER_RENDERING: 'true',
+      },
+    });
+    console.timeEnd('expo export');
+
+    console.time('expo serve');
+    await expoServe.startAsync([outputDir]);
+    console.timeEnd('expo serve');
+  });
+  test.afterAll(async () => {
+    await expoServe.stopAsync();
+  });
+
+  test('loads page without JavaScript errors', async ({ page }) => {
+    const pageErrors = pageCollectErrors(page);
+
+    await page.goto(expoServe.url.href);
+    await page.waitForSelector('[data-testid="index-text"]');
+
+    expect(pageErrors.errors).toEqual([]);
+  });
+
+  test('hydrates and performs client-side navigation from the links page', async ({ page }) => {
+    const pageErrors = pageCollectErrors(page);
+
+    await page.goto(new URL('/links', expoServe.url).href);
+    await page.waitForSelector('[data-testid="links-one"]');
+
+    await page.evaluate(() => {
+      (window as any).__e2eMarker = 'alive';
+    });
+
+    await page.locator('[data-testid="links-one"]').click();
+
+    await expect(page).toHaveURL(new URL('/about', expoServe.url).href);
+    await expect(page.locator('[data-testid="content"]')).toHaveText('About');
+
+    expect(
+      await page.evaluate(() => {
+        return (window as any).__e2eMarker;
+      })
+    ).toBe('alive');
+    expect(pageErrors.all).toEqual([]);
+  });
+});
diff --git a/packages/@expo/router-server/CHANGELOG.md b/packages/@expo/router-server/CHANGELOG.md
@@ -6,6 +6,9 @@
 
 ### 🎉 New features
 
+- Use stream rendering in SSR ([#43963](https://github.com/expo/expo/pull/43963) by [@hassankhan](https://github.com/hassankhan))
+- Add support for metadata in streaming SSR ([#44731](https://github.com/expo/expo/pull/44731) by [@hassankhan](https://github.com/hassankhan))
+
 ### 🐛 Bug fixes
 
 ### 💡 Others

diff --git a/packages/@expo/router-server/build/server/metadata.d.ts b/packages/@expo/router-server/build/server/metadata.d.ts
diff --git a/packages/@expo/router-server/build/server/metadata.d.ts.map b/packages/@expo/router-server/build/server/metadata.d.ts.map
diff --git a/packages/@expo/router-server/build/server/metadata.js b/packages/@expo/router-server/build/server/metadata.js
diff --git a/packages/@expo/router-server/build/server/metadata.js.map b/packages/@expo/router-server/build/server/metadata.js.map