Starting your first React Native app has minimal performance impact by itself. The app runs JavaScript code on a separate thread and communicates with native UI components. Smooth animations target 60 frames per second for a good user experience. Memory use is usually low at start but grows with added features. Battery use is moderate and depends on app activity.
To keep your React Native app running smoothly at 60fps, avoid heavy work on the main thread. Use useMemo and useCallback hooks to prevent unnecessary re-renders. Keep component trees shallow and avoid large inline functions. Use FlatList for long lists to render only visible items. Test on real devices to check frame rates.
The initial React Native app bundle is usually around 7-10MB, including the JavaScript runtime and native code. Startup time is typically 1-3 seconds on modern devices. Minimizing dependencies and assets helps reduce size. Use the Hermes engine on Android to improve startup speed and reduce memory.
On iOS, React Native uses the JavaScriptCore engine built into the system. On Android, you can enable Hermes for better performance. iOS apps require code signing with a valid Apple Developer account. Android apps need APK or AAB signing with a keystore. Debugging tools differ slightly: Xcode for iOS, Android Studio for Android.
For Apple App Store, ensure your app complies with Human Interface Guidelines: no placeholder content, proper privacy usage descriptions, and smooth UI. For Google Play, follow Material Design principles and provide a privacy policy if you collect data. Both stores require proper app icons, launch screens, and no crashes during review.
Your React Native app takes 5 seconds to load this screen. What is likely wrong?