React Native New Architecture: Solving Performance Bottlenecks with Fabric & TurboModules

Introduction

React Native has changed the way developers build cross-platform apps, but until recently, it still carried some architectural limitations. The old Bridge-based system sometimes led to performance bottlenecks, delayed UI updates, and inefficient communication between JavaScript and native code.

Enter the New Architecture powered by Fabric and TurboModules. Together, they redefine how React Native apps are rendered and how JavaScript interacts with native modules, making apps faster, smoother, and more future-proof.

This blog will walk you step by step through what Fabric and TurboModules are, how they work, and how you can start using them in your own apps.

Limitations of the Old Architecture

React Native’s legacy architecture relied on a “Bridge” mechanism that connected JavaScript and native code asynchronously. While innovative, this approach suffered from several drawbacks:

• Asynchronous bottleneck: All communication went through a single serialized bridge queue, often causing delays that impact responsiveness.
• Serialization/deserialization overhead: Data had to be converted back and forth between JS and native formats (JSON), leading to performance hits.
• UI lag: Updates to the UI could arrive out of sync with JavaScript state changes, especially problematic for complex animations or gesture-driven interfaces.
• Limited concurrency support: The old bridge was not designed to take advantage of React 18/19’s concurrent rendering features, making it difficult to build truly fluid experiences.

These limitations made the apps feel less native, especially on resource-constrained devices or in apps requiring rich interactivity.

 

 

What’s New in React Native’s New Architecture?

React Native’s New Architecture introduces two pivotal components, Fabric and TurboModules, along with Codegen as the glue binding them. Together, they revolutionize app rendering and native integration.

1. Fabric — The New Renderer

Fabric is React Native’s new rendering system, built in C++ and designed to integrate tightly with React’s concurrent features.

Key benefits of Fabric:

Faster UI updates thanks to synchronous rendering.

Better integration with React’s concurrent rendering.

More predictable layouts with Yoga v3.

Reduced lag between JS and UI.

Example: With Fabric enabled, a button press in your UI updates instantly without waiting for the JS bridge.

2. TurboModules — Faster Native Modules

TurboModules replace the traditional method of writing native modules by utilizing JSI (JavaScript Interface).

Why TurboModules matter:

No more JSON serialization between JS and native.

Direct function calls from JS to native.

Synchronous calls are possible where needed.

Lighter memory footprint since modules load on demand.

Example: If you have a DeviceInfo native module, you can call getDeviceName() instantly without waiting for an async bridge round trip.

3. Codegen — Glue Between JS & Native

Manually writing boilerplate is painful. Codegen automatically generates type-safe bindings between your JS/TS interfaces and native implementations.

Benefits:

Keeps JS and native in sync.

Reduces bugs from mismatched function signatures.

Saves time and effort when creating new modules.

Step-by-Step: Enabling the New Architecture

Android –

1. Open android/gradle.properties.

2. Add: 

3. Rebuild:

iOS –

1.Open ios/Podfile.

2. Add:

3. Install pods:

Note: Run console.log(global.nativeFabricUIManager) in JS to confirm Fabric is enabled.

 

Example: Creating a TurboModule

Let’s build a simple TurboModule that returns the device name.

1. Define the spec (TypeScript):

2. Implement natively (Android example):

3. Use in JS:

Real-Life Scenarios Where It Shines

• E-commerce apps: Product carousels and filters update faster.
• Messaging apps: Instant reactions & smooth chat updates.
• Streaming apps: Smoother video controls with minimal lag.
• Social media feeds: Endless scrolling feels native and fluid.

Best Practices for Migrating

• Start in a separate branch — don’t break production.
• Upgrade to React Native 0.76+ (stable new-arch support).
• Check your libraries — some may not yet support Fabric/TurboModules.
• Use Codegen for all new native modules.
• Test thoroughly on both Android and iOS.

Limitations

• Third-party library support: Not all libraries have been updated yet.
• Build complexity: Initial builds take longer due to C++ compilation.
• Learning curve: Native devs may need time to adapt to Codegen & JSI.
• Over-optimizing early: Only migrate modules where performance matters most.

Communicating to Stakeholders

If you’re explaining this to non-technical stakeholders:

• Faster UI = happier users.
• Smoother animations = stronger engagement.
• Better architecture = long-term scalability.
• Compatibility with React’s future = future-proof investment.

The Future of React Native Performance

React Native is actively evolving:

• Fabric and TurboModules are now the default going forward.
• React 19 features, such as concurrent rendering, will be fully integrated.
• Hermes engine is the standard JS engine for optimal performance.
• Expect even smoother dev tools and better cross-platform alignment.

Conclusion

The React Native New Architecture is a leap forward, delivering faster rendering, smoother interfaces, and seamless native integration. By adopting Fabric and TurboModules, developers can build performant, scalable apps ready for the future of React.