Which framework delivers the best startup performance and UI smoothness in 2025—Flutter or React Native?

Compares cold/warm start times, frame-rate consistency, memory use, and smoothness on low-end devices.

• Flutter bootstraps in ~1.2 s (cold) and ~85 ms (warm), maintains stable 60–120 fps animations, and exhibits lower memory usage thanks to its Impeller engine and AOT compilation. • React Native, with Fabric, JSI, and bridging improvements, boots in ~1.4–1.6 s and averages 45–55 fps under heavy UI, with higher memory use—~162 MB compared to Flutter's ~148 MB turn0search7turn0search6turn0search2. Flutter consistently leads for performance-intensive interfaces, especially on budget hardware. Tags: flutter, react-native, performance, startup-time, memory, ui