Flutter apps run at a smooth 60fps or higher by compiling to native ARM code. This direct compilation avoids JavaScript bridges, reducing lag and improving battery life. Flutter's rendering engine redraws only changed parts, saving CPU and memory. However, complex animations or heavy widgets can increase memory use, so keep UI simple for best performance.
To keep Flutter apps fast, minimize widget rebuilds by using const constructors and ValueNotifier or Provider for state management. Use Flutter's RepaintBoundary to isolate parts of the UI that change often. Avoid large images or heavy computations on the main thread. Profile your app with Flutter DevTools to spot slow frames and memory leaks.
Flutter apps include the Flutter engine, which adds about 4-5MB to the app size. This is a trade-off for cross-platform support and smooth UI. Use Flutter's tree shaking to remove unused code and compress assets to reduce size. Startup time is usually under 2 seconds, but large initializations or many plugins can slow it down. Lazy load features when possible.
Flutter uses the same codebase for iOS and Android, but platform-specific differences exist. iOS requires code signing and provisioning profiles, while Android needs APK or AAB signing. Flutter handles UI rendering identically on both, but native plugins may behave differently. Testing on both platforms is essential to catch platform-specific issues.
For iOS, follow Apple's Human Interface Guidelines for UI and privacy. Ensure your app requests permissions clearly and only when needed. For Android, comply with Google Play policies on permissions and content. Both stores require proper app icons, launch screens, and privacy policies. Flutter apps must pass these checks like any native app.
Your Flutter app takes 5 seconds to load this screen. What's likely wrong?