Running Rust code directly in React Native

This project demonstrates how to integrate Rust into a React Native application and run Rust code natively on both iOS (Swift) and Android (Kotlin). It uses UniFFI to generate language bindings automatically and leverages modern tooling such as .xcframework for iOS (so you don’t need to manually manage simulator/device builds).

The goal is to provide the simplest possible example of wiring Rust into a React Native project while keeping the setup clean and future-proof.

🚀 Getting Started

Clone the repo and install dependencies:

npm install

Then you can run the example on iOS or Android:

npm run ios
npm run android

✨ Features

• 🔧 UniFFI support: Simplifies exposing Rust functions to Swift and Kotlin.
• 📱 Cross-platform bindings: Works with iOS and Android out of the box.
• ⚡ React Native integration: Call Rust code directly from your JS/TS code.
• 📦 Modern iOS build system: Uses .xcframework for easy simulator/device handling.
• 🛠 Minimal example: Focused on clarity, this is a pure minimalistic example so you can see the bare minimum required to run your rust code directly in native code.

⚙️ How It Works

1. native_rust_lib library The business logic lives in a separate Rust library, native_rust_lib. Functions you want to expose must use #[uniffi::record], which ensures they are included in the generated bindings via procmacros

2. UniFFI code generation UniFFI automatically generates Swift and Kotlin bindings from the annotated Rust code using ProcMacros.

3. Native module integration React Native bridges the generated Swift/Kotlin code so you can call it from JavaScript/TypeScript.

4. React Native usage In your JS/TS files, you can import and use the exposed functions as if they were ordinary native modules.

Building rust code

I have also included instructions on how you can build your own library and use that in your React-Native project. The scripts build-ios and build-android will:

• Compile your Rust code for the proper mobile targets
• Package the output into an .xcframework (for iOS) and .aar (for Android).
• Move the files to the correct folders in your React Native project.

cargo run --release --bin build-ios
cargo run --release --bin build-android