react-nativearchitectureperformance

Migrating from Expo CLI to React Native CLI (New Architecture)

January 15, 202612 min read

Why Migrate?
Expo managed workflow is great for getting started quickly, but as your app grows, you may need:
- Custom native modules
- Better control over native code
- Access to the new React Native architecture (Fabric + TurboModules)

Prerequisites
Before starting the migration, ensure you have:
1. Xcode 15+ installed
2. Android Studio with NDK configured
3. Node.js 18+
4. A backup of your current project

Step 1: Eject from Expo
```bash
npx expo prebuild
```
This generates the `ios/` and `android/` folders with native code.

Step 2: Enable New Architecture
#

iOS
In `ios/Podfile`, add:
```ruby
ENV['RCT_NEW_ARCH_ENABLED'] = '1'
```
#

Android
In `android/gradle.properties`:
```properties
newArchEnabled=true
```

Step 3: Handle Native Module Migration
Most Expo modules work out of the box, but you may need to update some:
- `expo-camera` → Native iOS/Android permissions
- `expo-notifications` → Firebase Cloud Messaging setup
- `expo-file-system` → Direct RNFS integration

Common Pitfalls
1. Build failures: Clear derived data and rebuild
2. Metro bundler issues: Reset cache with `npx react-native start --reset-cache`
3. Native linking: Run `pod install` after any native dependency changes

Conclusion
Migration requires patience, but the benefits of the new architecture—better performance, improved memory management, and synchronous native calls—are worth the effort.