File: server-components.md | Updated: 11/15/2025
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Learn about rendering React components on the server in Expo.
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Experimentally available in SDK 52 and later. This is a beta release and subject to breaking changes.
React Server Components enable a number of exciting capabilities, including:
Expo Router enables support for React Server Components on all platforms. This is an early preview of a feature that will be enabled by default in Expo Router.
Your project must use Expo Router and React Native new architecture (default from SDK 52).
To use React Server Components in your Expo app, you need to:
react-server-dom-webpack@19.0.0-rc-6230622a1a-20240610 (react-server-dom-webpack@~19.0.0 for SDK 53 and later).expo-router/entry (default) in package.json.app.json
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{ "expo": { "experiments": { "reactServerFunctions": true } } }
"origin" is not set to a boolean value anywhere in your app config.app/index.tsx (Client Component)
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/// <reference types="react/canary" /> import React from 'react'; import { ActivityIndicator } from 'react-native'; import renderInfo from '../actions/render-info'; export default function Index() { return ( <React.Suspense fallback={ // The view that will render while the Server Function is awaiting data. <ActivityIndicator /> }> {renderInfo({ name: 'World' })} </React.Suspense> ); }
actions/render-info.tsx (Server Function)
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'use server'; import { Text } from 'react-native'; export default async function renderInfo({ name }) { // Securely fetch data from an API, and read environment variables... return <Text>Hello, {name}!</Text>; }
The views return value of the Server Function is a React Server Component payload that will be streamed to the client.
web.outputmust besinglein the app config during the developer preview. Support for more output modes is coming soon.
Server Components run in the server, meaning they can access server APIs and Node.js built-ins (when running locally). They can also use async components.
Consider the following component which fetches data and renders it:
components/pokemon.tsx
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import 'server-only'; import { Image, Text, View } from 'react-native'; export async function Pokemon() { const res = await fetch('https://pokeapi.co/api/v2/pokemon/2'); const json = await res.json(); return ( <View style={{ padding: 8, borderWidth: 1 }}> <Text style={{ fontWeight: 'bold', fontSize: 24 }}>{json.name}</Text> <Image source={{ uri: json.sprites.front_default }} style={{ width: 100, height: 100 }} /> {json.abilities.map(ability => ( <Text key={ability.ability.name}>- {ability.ability.name}</Text> ))} </View> ); }
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To render this as a server component, you'll need to return it from a Server Function.
useState, useEffect, or useContext in Server Components."use server" is not meant to mark a file as a server component. It's used to mark a file as having React Server Functions exported from it.Since Server Components cannot access native APIs or React Context, you can create a Client Component to use these features. They are created by marking files with the "use client" directive at the top.
components/button.tsx
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'use client'; import { Text } from 'react-native'; export default function Button({ title }) { return <Text onPress={() => {}}>{title}</Text>; }
This module can be imported and used in a Server Function or Server Component.
You cannot pass functions as props to Server Components. You can only pass serializable data.
Server Functions are functions that run on the server and can be called from Client Components. Think of them like fully-typed API routes that are easier to write.
They must always be an async function and are marked with "use server" at the top of the function.
app/index.tsx
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export default function Index() { return ( <Button title="Press me" onPress={async () => { 'use server'; // This code runs on the server. console.log('Button pressed'); return '...'; }} /> ); }
You can create a Client Component to invoke the Server Function:
components/button.tsx
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'use client'; import { Text } from 'react-native'; export default function Button({ title, onPress }) { return <Text onPress={() => onPress()}>{title}</Text>; }
Server Functions can also be defined in a standalone file (with "use server" at the top) and imported from Client Components:
components/server-actions.tsx
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'use server'; export async function callAction() { // ... }
These can be used in a Client Component:
components/button.tsx
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import { Text } from 'react-native'; import { callAction } from './server-actions'; export default function Button({ title }) { return <Text onPress={() => callAction()}>{title}</Text>; }
React Server Functions in Expo Router can render React components on the server and stream back an RSC payload (a custom JSON-like format that's maintained by the React team) for rendering on the client. This is similar to server-side rendering (SSR) on the web.
For example, the following Server Function will render some text:
components/server-actions.tsx
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'use server'; // Optional: Import "server-only" for sanity. import 'server-only'; import { View, Image, Text } from 'react-native'; export async function renderProfile({ username, accessToken, }: { username: string; accessToken: string; }) { // NOTE: Rate limits, GDPR, and other server-side operations can be done here. // Fetch some data securely from an API. const { name, image } = await fetch(`https://api.example.com/profile/${username}`, { headers: { Authorization: `Bearer ${accessToken}`, // Use secret environment variables securely as this code will live on the server. // The EXPO_PUBLIC_ prefix is not required here. 'X-Secret': process.env.SECRET, }, }).then(res => res.json()); // Render return ( <View> <Image source={{ uri: image }} /> <Text>{name}</Text> </View> ); }
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This Server Function can be invoked from a Client Component and the contents will be streamed back to the client:
components/profile.tsx
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'use client'; import { useLocalSearchParams } from 'expo-router'; import * as React from 'react'; import { Text } from 'react-native'; import { renderProfile } from '@/components/server-actions'; // Loading state that renders while data is being fetched. function Fallback() { return <Text>Loading...</Text>; } export default function Profile() { const { username } = useLocalSearchParams(); const { accessToken } = useCustomAuthProvider(); // Call the Server Function with the username and access token. const profile = React.useMemo( () => renderProfile({ username, accessToken }), [username, accessToken] ); // Render the profile asynchronously with React Suspense and a custom loading state. return <React.Suspense fallback={<Fallback />}>{profile}</React.Suspense>; }
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Not all libraries are optimized for React Server Components yet. You can use the "use client" directive to mark a file as a Client Component and use it in a Server Component. This can be used to temporarily workaround compatibility issues.
For example, consider a library react-native-unoptimized that does not ship with "use client" directives yet. You can workaround this by creating a module and re-exporting each module:
lib/react-native-unoptimized.tsx
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// This directive opts the module into client-side rendering. 'use client'; // Re-exporting the imports from the library. export { One, Two, Three } from 'react-native-unoptimized';
Avoid using export * from '...' as this breaks some of the internals of interopting between the server and client.
Modules marked with "use client" cannot be dot-accessed from Server Components. This means operations like StyleSheet.create or Platform.OS will not work on the server without further optimization in the react-native package.
You can stream back partial UI from the server while waiting for data to load by using React Suspense.
In the following example, a Loading... text is returned instantly on the client, and when the <MediumTask> finishes rendering one second later, it will replace the text with Medium task done!. The <ExpensiveTask> will take three seconds to load, and when it finishes, it will replace the text with Expensive task done!.
app/index.tsx (Client Component)
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import { Suspense } from 'react'; import { renderMediumTask, renderExpensiveTask } from '@/actions/tasks'; export default function App() { return <Suspense fallback={<Text>Loading...</Text>}>{renderTasks()}</Suspense>; }
actions/tasks.tsx (Server Functions)
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'use server'; export async function renderTasks() { return ( <Suspense fallback={<Text>Loading...</Text>}> <> <MediumTask /> <Suspense fallback={<Text>Loading...</Text>}> <ExpensiveTask /> </Suspense> </> </Suspense> ); } async function MediumTask() { // Wait one second before resolving. await new Promise(resolve => setTimeout(resolve, 1000)); return <Text>Medium task done!</Text>; } async function ExpensiveTask() { // Wait three seconds before resolving. await new Promise(resolve => setTimeout(resolve, 3000)); return <Text>Expensive task done!</Text>; }
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If you remove the Suspense wrapper around <ExpensiveTask>, you'll see that the Loading... waits for both components to finish rendering before updating the UI. This enables you to control the loading state incrementally. Sometimes, it makes sense to wait for everything to load at once (most of the time), while other times, it is beneficial to stream back UI as soon as you have (like the text response in ChatGPT).
Server Components can access secrets and server-side APIs. You can use the process.env object to access environment variables. You can ensure a module never runs on the client by importing the server-only module in your project.
actions/renderData.tsx
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// This will assert if the module runs on the client. import 'server-only'; import { Text } from 'react-native'; export async function renderData() { // This code only runs on the server. const data = await fetch('https://my-endpoint/', { headers: { Authorization: `Bearer ${process.env.SECRET}`, }, }); // ... return <div />; }
You can define the secret in your .env file:
.env
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SECRET=123
You do not need to restart the dev server to update environment variables. They are automatically reloaded on every request.
To detect which platform your code is bundled for, use the process.env.EXPO_OS environment variable. For example, process.env.EXPO_OS === 'ios'. Prefer this to Platform.OS as react-native is not fully optimized for React Server Components yet and won't work as expected.
You can detect if code is running on the server by performing a typeof window === 'undefined' check. This will always return true on client devices and false on the server.
Library authors can test their modules support Server Components by using jest-expo. Learn more in the Testing React Server Components
guide.
React Server Components are a feature of React 19. To enable them, Expo CLI automatically uses a special canary build of React on all platforms. In the future, it will be removed when React 19 is enabled by default in React Native.
As a result, you can use React 19 features such as placing <meta> tags anywhere in your app (web-only).
app/index.tsx
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export default function Index() { return ( <> {process.env.EXPO_OS === 'web' && ( <> <meta name="description" content="Hello, world!" /> <meta property="og:image" content="/og-image.png" /> </> )} <MyComponent /> </> ); }
You can use this instead of the Head component from expo-router/head, but it only works on web for now.
You can access the request headers used to make the request to the Server Component using the expo-router/rsc/headers module.
actions/renderHome.tsx
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import { unstable_headers } from 'expo-router/rsc/headers'; export async function renderHome() { const authorization = (await unstable_headers()).get('authorization'); return <Text>{authorization}</Text>; }
The unstable_headers function returns a promise that resolves to a read-only Headers object.
render: 'static') because the headers dynamically change based on the request. In the future, this API will assert if the output mode is static.unstable_headers is server-only and cannot be used on the client.Full React Server Components mode
This mode is even more experimental!
Enabling full React Server Components support allows you to leverage even more features. In this mode, the default rendering mode for routes is server components instead of client components. It is still in development, as the Router and React Navigation need to be rewritten to support concurrency.
To enable full Server Components mode, you need to enable the reactServerComponentRoutes flag in the app config:
app.json
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{ "expo": { "experiments": { "reactServerFunctions": true, "reactServerComponentRoutes": true } } }
With this enabled, all routes will render as Server Components by default. In the future this will reduce server/client waterfalls and enable build-time rendering to provide better offline support.
Stack, Tabs, and Drawer, do not support Server Components yet.Link component props are not supported yet.This is limited to full React Server Components mode.
Server Components are reloaded on every request in development. This means that you can make changes to your server components and see them reflected immediately in the client runtime. You may want to manually trigger a reload event programmatically to refetch data or re-render the component. This can be done using the router.reload() function from the useRouter hook.
components/button.tsx
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'use client'; import { useRouter } from 'expo-router'; import { Text } from 'react-native'; export function Button() { const router = useRouter(); return ( <Text onPress={() => { // Reload the current route. router.reload(); }}> Reload current route </Text> ); }
If the route was rendered at build-time, it will not be re-rendered on the client. This is because the rendering code is not included in the production server.
This is limited to full React Server Components mode.
Expo Router supports two different modes of rendering Server Components: build-time rendering and request-time rendering. These modes can be indicated on a per-route basis by using the unstable_settings export:
app/index.tsx
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import { Text, View } from 'react-native'; export const unstable_settings = { // This component will be rendered at build-time and never re-rendered in production. render: 'static', }; export default function Index() { return ( <View> <Text>Hello, world!</Text> </View> ); }
render: 'static' will render the component at build-time and never re-render it in production. This is similar to how classic static site generators work.render: 'dynamic' will render the component at request-time and re-render it on every request. This is similar to how server-side rendering works.If you want client-side rendering, move your data fetching to a Client Component and control the rendering locally.
Routes marked with static output will be rendered at build-time and embedded in the native binary. This enables rendering routes without making a server request (because the server request was made when the app was downloaded).
The current default is dynamic rendering. In the future, we'll change the caching and optimizations to be smarter and more automatic.
You can generate static pages at build-time with the generateStaticParams function. This is useful for components that must only run at build-time and not on the server.
app/shapes/[shape].tsx
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import { Text } from 'react-native'; // Adding `unstable_settings.render: 'static'` will prevent this component from running on the server. export const unstable_settings = { render: 'static', }; // This function will generate static pages for each shape. export async function generateStaticParams() { return [{ shape: 'square' }]; } export default function ShapeRoute({ shape }) { return <Text>{shape}</Text>; }
This is limited to full React Server Components mode.
Expo Router supports importing global CSS and CSS modules in Server Components.
app/index.tsx
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import './styles.css'; import styles from './styles.module.css'; export default function Index() { return <div className={styles.container}>Hello, world!</div>; }
The CSS will be hoisted into the client bundle from the server.
Universal React Server Components are still in beta.
First, build the web project:
Terminal
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- npx expo export -p web
Then you can host it locally with npx expo serve or deploy it to the cloud:
Deploy instantly with EAS
EAS Hosting is the best way to deploy your Expo API routes and servers.
You can deploy your native React Server Components by following the server deployment guide:
Deploy native servers to EAS
Deploy and link versioned servers to your production native apps.
This is a very early technical preview that we're actively developing.
generateStaticParams
is only partially supported in full React Server Components mode.form integration with Server Functions is not supported yet (this partially works automatically, but data is not encrypted).StyleSheet.create and Platform.OS are not supported on native. Use standard objects for styles and process.env.EXPO_OS for platform detection.