Introduction to Development Builds

Learn about development builds and when to use them instead of Expo Go.

Development builds are custom versions of the Expo Go app that include your app’s native code and third-party libraries. They provide a development environment closer to your production app while maintaining fast iteration speeds.

What are Development Builds?

A development build is a debug build of your app that includes the expo-dev-client package. Unlike Expo Go, which has a fixed set of native modules, development builds contain exactly the native code your app needs.

Development builds include:

• Custom native modules - Any native module from npm or your own native code
• Dev client UI - A launcher screen to load different versions of your JavaScript
• Enhanced debugging - Improved network inspection, error boundaries, and developer menu
• Fast iteration - Hot reloading and fast refresh for JavaScript changes

Expo Go vs Development Builds

Feature	Expo Go	Development Build
Native modules	Fixed set included	Any module you install
Setup time	Instant (just download)	Requires initial build (~10-20 min)
JS iteration	Instant reload	Instant reload
Native changes	Not possible	Requires rebuild
Production-like	No	Yes

When to Use Development Builds

You should use development builds when:

1. Using Custom Native Modules

If your app requires native modules not included in Expo Go:

app.json

{
  "expo": {
    "plugins": [
      "expo-camera",
      "expo-media-library",
      ["expo-build-properties", {
        "android": { "minSdkVersion": 24 }
      }]
    ]
  }
}

2. Testing Native Configuration

When you need to test platform-specific settings:

• iOS entitlements and capabilities
• Android permissions and manifest configurations
• Custom app icons, splash screens, or schemes
• Native build properties (SDK versions, architectures)

3. Preparing for Production

Development builds use the same native code as production:

# Same native code for development and production
npx expo run:ios --configuration Release
npx expo run:android --variant release

4. Working in Teams

Share builds with teammates without Xcode or Android Studio:

• iOS: Distribute via TestFlight or ad-hoc provisioning
• Android: Share APK files directly

Benefits

Faster Development Workflow

Once the initial build is complete, you get:

• Instant JavaScript reloads
• No need to rebuild for JS changes
• Hot module replacement
• Fast refresh

Production Parity

Your development environment matches production:

• Same native dependencies
• Same build configuration
• Same bundling process
• Same performance characteristics

Enhanced Developer Experience

expo-dev-client adds powerful tools:

import { useDevToolsPluginClient } from 'expo/devtools';

export function MyComponent() {
  const client = useDevToolsPluginClient('my-plugin');
  
  // Enhanced debugging capabilities
  client?.sendMessage('debug', { data: 'test' });
}

Flexible Deployment Options

• Test multiple JavaScript bundles without rebuilding
• Load PR previews instantly
• Switch between development servers
• Test updates and rollbacks

Development Build Workflow

A typical development workflow:

1. Install expo-dev-client

   npx expo install expo-dev-client
   
2. Create a development build

   # Local build
   npx expo run:ios
   npx expo run:android
   
   # Or cloud build with EAS
   eas build --profile development --platform ios
   
3. Start the dev server

   npx expo start --dev-client
   
4. Iterate on JavaScript

   Make changes to your JavaScript code - they reload instantly.

5. Rebuild when needed

   Only rebuild when you:

   • Install new native modules
   • Change native configuration
   • Update app.json plugins

Cost Considerations

Local Builds (Free)

• Build on your own machine
• Requires Xcode (iOS) or Android Studio (Android)
• Full control over build environment

EAS Build (Paid)

• Cloud building service
• No local tooling required
• Faster builds on powerful servers
• Free tier available

Next Steps

Creating Builds

Learn how to create your first development build

Installation

Install builds on your devices

Debugging

Debug your development builds

Testing

Set up testing for your app