React Native vs Flutter - I built the same chat app with both

Cross-platform mobile development comes down to a tradeoff between Flutter’s “batteries-included” approach and React Native’s JavaScript-first flexibility—but the biggest practical difference shows up in how each framework renders UI and how much friction developers face while building and iterating.

Flutter, built by Google, uses Dart and its own rendering engine to draw UI directly. Instead of relying on native UI components, Flutter compiles to native code and renders its own pixels (via a C++ engine and Skia). That design reduces reliance on a JavaScript-to-native bridge, which is central to React Native’s architecture. The result is typically smoother performance and more consistent visuals across iOS and Android, with the added ability to paint custom graphics like a game engine. When native features are needed, Flutter uses platform channels to communicate with the device layer.

React Native, from Facebook, is built around JavaScript and React. It runs two JavaScript threads—one for the app’s main work and one for business logic—and uses a bridge to pass serialized messages between JavaScript and native code. UI components ultimately become truly native on each platform, not a “web app in a wrapper,” but the bridge still shapes performance characteristics and can become a bottleneck as apps grow. React Native’s philosophy is minimal: it provides base components and expects developers to assemble the rest from third-party libraries, which can mean more dependency management and more choices.

The developer experience mirrors those philosophies. React Native starts with npx react-native init (or often Expo) and produces a project full of configuration and tooling files—Metro for hot reloading, Watchman for file watching, Babel for transpiling, and build tooling like Buck. Iteration relies on Metro plus hot reload, which preserves app state while reflecting code changes. But the ecosystem is more “choose your own adventure”: teams may add TypeScript, adopt Ignite for boilerplate, or swap in Expo depending on preferences.

Flutter’s setup is typically faster because it doesn’t require pulling in as many packages up front, and the Flutter extension in VS Code can manage dependencies automatically. Code lives in main.dart with configuration in pubspec.yaml. Dart’s type system and null safety provide stronger guardrails during development, catching many issues before runtime—an advantage for mobile apps where app-store reviews make bugs expensive. Flutter also supports hot reload (leveraging just-in-time compilation), and its tooling can surface documentation and type information directly in the editor.

Both frameworks use declarative UI trees inspired by React: React Native uses JSX with components like View, while Flutter uses classes with a build method that returns a widget tree. Flutter’s approach can lead to deeply nested widget structures that are harder to read unless developers extract custom widgets, while React Native can require more work to find or create components that match exactly what the UI needs—especially when desired libraries don’t support React Native.

After building the same chat app with Firebase as the backend, the performance picture leans toward Flutter in benchmarks, often getting closer to native 60fps targets. Still, the transcript cautions that for many real-world apps, performance differences may be indistinguishable to users, making the choice less about raw speed and more about ecosystem fit, developer workflow, and how comfortable teams are with Dart versus JavaScript.