Flutter’s Impeller vs. React Native’s Fabric - Who Wins in UI Rendering?

Cross-platform development has evolved rapidly, and one of the biggest battlegrounds today is UI performance. Flutter and React Native-the two dominant players-are both introducing new rendering engines:

Flutter’s Impeller (replacing Skia for better frame rendering)
React Native’s Fabric (redesigning the UI thread for faster interactions)
Both aim to make UI rendering smoother, faster, and more efficient, but which one truly wins? Let’s dive deep!

Why Do Rendering Engines Matter?

Before we get into the details, let’s understand why rendering engines are so important for cross-platform apps:

• Smooth UI Animations – Users expect 60fps (or even 120fps) experiences.
• Reduced Jank (Lag) – No one likes frame drops while scrolling.
• Efficient GPU Usage – Poor rendering can drain battery life.
• Seamless Native Interactions – UI should feel native, not like a web wrapper

Both Impeller and Fabric attempt to solve the limitations of their previous rendering engines (Skia in Flutter, Shadow Tree in React Native).

What’s New in Flutter’s Impeller?

Impeller is Flutter’s next-gen rendering engine, replacing Skia.
Here’s why it’s a game-changer:

• Precompiles shaders – Skia compiled shaders at runtime, causing lag; Impeller does this ahead of time for smoother rendering.
• Better GPU utilization – Uses low-level APIs like Metal (iOS) and Vulkan (Android) for faster rendering.
• Fixes janky animations – With shader caching, scrolling, and animations become consistent.
• More predictable frame rates – No more sudden performance dips due to on-the-fly shader compilation.

What’s New in React Native’s Fabric?

Fabric is a complete re-architecture of how React Native renders UI components.
Key improvements include:

• Asynchronous rendering – React Native now renders components in a background thread for better performance.
• JavaScript Interface (JSI) replaces the Bridge – Fabric eliminates the old “React Native Bridge” for faster communication with native code.
• Concurrent Rendering Support – Fabric works better with React 18’s concurrent mode for smoother UI updates.
• Native component interoperability – Making it easier to reuse existing native UI components with better performance.

Comparative Analysis:

Flutter’s Impeller boosts rendering by precompiling shaders, reducing lag, and ensuring smooth animations-perfect for graphics-heavy apps. React Native’s Fabric, on the other hand, enhances UI responsiveness with asynchronous rendering and JSI, making dynamic updates faster and more native-like. Impeller excels in GPU efficiency, while Fabric optimizes threading for smoother UI interactions. If you need high-performance animations, go with Impeller; for dynamic, frequently updating UIs, Fabric is the better choice.

Where Does NativeBridge Fit In?

At NativeBridge.io, we let developers run native apps in any browser with a simple link no setup, and no friction.

• For React Native (Fabric): Seamless native module integration with JSI and async rendering.
• For Flutter (Impeller): Low-overhead bridging for GPU-optimized UIs and smooth animations.

If you're working with Fabric or Impeller, NativeBridge.io helps you test, preview, and share apps effortlessly. Try it out!