Development builds

A development build is your app with expo-dev-client compiled in. It contains no JavaScript of its own: it loads your code from Metro on your machine, so edits appear on the device in a second or two with Fast Refresh. You rebuild only when native code or config changes.

	Development build	Preview / internal build
JavaScript	Loaded live from Metro	Bundled into the app at build time
Hot reload	Yes	No: every change needs a new build and reinstall
Build configuration	Debug / assembleDebug	Release / assembleRelease
For	You, while coding	Testers

Setup

npx expo install expo-dev-client

Then two profiles: one for the iOS Simulator, one for real devices.

{
  "build": {
    "development": {
      "developmentClient": true,
      "distribution": "internal",
      "ios": { "simulator": true }
    },
    "development-device": {
      "developmentClient": true,
      "distribution": "internal"
    }
  }
}

On Android the two are the same: a debug .apk runs on emulators and devices alike.

In the iOS Simulator

No signing needed.

rnd build -p ios -e development
rnd build:download -p ios
cd build && unzip *.zip && tar -xzf *-simulator.tar.gz
xcrun simctl install booted *.app

npx expo start --dev-client     # press i, or open the app and pick the server

On your phone

A device build is signed with your ad-hoc profile, so it installs only on the devices that profile lists. Set that up once in Internal distribution.

rnd build -p all -e development-device

When the build finishes, open its Install QR in the dashboard, scan it with the phone and install. Then start Metro so the phone can reach it over your network:

npx expo start --dev-client --lan

Open the app on the phone. Its launcher lists development servers it finds on your network; tap yours. You can also scan the QR code expo start prints in an interactive terminal, or encode this URL yourself:

exp+<slug>://expo-development-client/?url=http%3A%2F%2F<your-computer-ip>%3A8081

The phone must reach your computer

• Same Wi-Fi network, and no client isolation on it.
• The first launch asks for Local Network access: allow it, or the app cannot find Metro.
• On iOS 16 or later, Developer Mode must be on (Settings → Privacy & Security).
• Different networks? npx expo start --dev-client --tunnel relays through a public URL.

Same app, same slot

Development, preview and production builds share a bundle identifier, so installing one replaces the other on the phone.