> For the complete documentation index, see [llms.txt](https://docs.appetize.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.appetize.io/guides-and-samples/development-loop/react-native.md).

# React Native

Use Metro and Fast Refresh so a save updates the running app.

Use Metro and Fast Refresh so a save updates the running app and keeps its state. An agent can set this up from one prompt.

## Ask your agent

Install the CLI and its agent skill first:

```bash
npm install -g @appetize/cli
appetize skill install
```

Then paste this into Claude Code, Cursor, Codex, or another coding agent:

{% code overflow="wrap" %}

```
Set up the Appetize AI development loop for this React Native app.

1. Install expo-dev-client if it is missing. Build a development build: an Android x86_64 debug APK, or on a Mac a zipped iOS simulator .app. Upload it with `appetize build upload <file> --wait` and keep the build id.
2. Start Metro in the background with `npx expo start --dev-client --tunnel`. Copy the exp+ URL it prints.
3. Run `appetize session start <device> --target <build-id>` on the device I name, or pixel7. Then run `appetize open '<exp+ URL>'`. If the Development Build launcher shows, run open again. Tap Continue if a developer menu appears. Give me the viewerUrl.
4. Confirm the app loaded with `appetize inspect`. Then make my change, save it, and check the screen with `appetize screenshot`. Don't rebuild unless I change native code.
```

{% endcode %}

Then ask for changes, like "make the dice spin when it rolls." The agent saves, Metro updates the app, and the agent checks the screen.

## Or run it yourself

These are the steps the agent runs.

### 1. Upload a development build

```bash
npx expo install expo-dev-client
```

Android:

```bash
npx expo prebuild --platform android
cd android && ./gradlew assembleDebug -PreactNativeArchitectures=x86_64
appetize build upload <apk> --wait
```

iOS, on a Mac:

```bash
npx expo run:ios
zip -r MyApp.zip MyApp.app
appetize build upload <zip> --wait
```

The upload prints an `id`. That is `<build-id>`. Older docs call it the public key.

### 2. Start Metro

```bash
npx expo start --dev-client --tunnel
```

Copy the `exp+` URL it prints. That is `<metro-url>`.

### 3. Open the app

```bash
appetize session start <device> --target <build-id>
appetize open '<metro-url>'
```

`<device>` comes from `appetize device list`, such as `pixel7` or `iphone15pro`.

If the Development Build launcher shows, run `open` again. Tap **Continue** if a developer menu appears.

Open the `viewerUrl` from `session start` beside your editor.

### 4. Save, then look

Save a file. The screen updates and the app stays open.

```bash
appetize session stop
```

## Without Expo

Start Metro with `npx react-native start`. On Android, `adb reverse tcp:8081 tcp:8081` points the device at it. On iOS, Metro needs a URL the simulator can reach.