A few years ago, mobile app development meant two separate teams and two separate codebases: one in Swift/Objective-C for iOS, another in Kotlin/Java for Android. React Native changed that equation.
What is React Native?
Developed by Meta, React Native is a framework that lets you build real (native) iOS and Android apps using JavaScript and React. Unlike hybrid solutions that show a web app inside a WebView, React Native uses the platform's own components.
"Learn once, write anywhere" — A single JavaScript codebase produces native apps that run on both iOS and Android.
Key Advantages
- Single codebase: 70-80% code sharing between iOS and Android
- Development speed: Low learning curve for web developers
- Hot Reload: See code changes live within seconds
- Large ecosystem: Thousands of ready-made libraries and components
- Production use by Meta and major companies (Instagram, Shopify)
Architecture: New Architecture
React Native's new architecture (JSI — JavaScript Interface) completely redesigned the bridge between JavaScript and native code. Instead of the old JSON-based async bridge, JSI allows the JavaScript engine to access native APIs directly and synchronously.
- JSI (JavaScript Interface): Synchronous native module access
- Fabric: New render engine with fewer unnecessary re-renders
- TurboModules: Lazy-loaded native modules on demand
- Hermes: Optimized JS engine developed by Facebook
Lessons from Real Projects
We've learned some important lessons while using React Native in our mobile app projects:
- Use Redux Toolkit or Zustand for state management; Context API can cause performance issues in large apps
- Use FlatList and VirtualizedList for image-heavy screens; remember that ScrollView renders all items at once
- Use Platform.OS for platform-specific code; too many platform branches reduces code readability
- Use react-native-reanimated to run animations on the native thread instead of the JavaScript thread
Conclusion
For most business and commercial mobile apps, React Native offers the best balance between speed, cost, and quality. With the right tools and an experienced team, native-quality iOS and Android apps can be built from a single codebase.