React Native Reanimated improves animation smoothness by running animations on the native thread instead of the JavaScript thread. This reduces frame drops and jank, helping your app maintain a steady 60fps or higher on supported devices. It also lowers CPU usage on the JavaScript side, which can save battery life. However, complex animations or excessive use of animated nodes can increase memory usage, so keep animations efficient.
To keep animations smooth at 60fps, use Reanimated's worklets to run animation logic directly on the native side. Avoid heavy computations inside animations. Use useAnimatedStyle and withTiming or withSpring for performant transitions. Minimize re-renders by separating animated components from others. Profile animations with React Native's performance tools and reduce unnecessary animated nodes.
Adding React Native Reanimated increases your app bundle size moderately because it includes native modules and JavaScript helpers. Expect an increase of a few megabytes depending on your app. This can slightly affect startup time, especially on low-end devices. To reduce impact, enable Proguard (Android) and dead code elimination (iOS) to strip unused code. Lazy load animations when possible to improve initial load.
React Native Reanimated supports both iOS and Android with native modules. On iOS, it uses Objective-C/Swift native code, while on Android it uses Java/Kotlin. Installation requires different native setup steps per platform, including CocoaPods for iOS and Gradle config for Android. Performance is generally similar, but Android devices vary more in hardware, so test animations on multiple devices. iOS tends to have more consistent frame rates.
Ensure your app complies with Apple and Google guidelines when using Reanimated. Avoid animations that cause excessive battery drain or interfere with accessibility. Provide fallback or disable animations for users who prefer reduced motion (check accessibilityReduceMotionEnabled). Test that animations do not block UI responsiveness or cause crashes. Sign your app properly with native modules included.
Your app takes 5 seconds to load this screen with animations. What's likely wrong?