Hermes

Hermes is an open-source JavaScript engine optimized for fast-start React Native applications on mobile platforms.

Engineered by Meta, Hermes tackles the performance bottlenecks of mobile JavaScript execution by shifting work from runtime to build time. It utilizes ahead-of-time (AOT) compilation to transform source code into compact bytecode, significantly reducing Time to Interactive (TTI) and memory overhead compared to traditional JIT engines. By prioritizing a smaller binary footprint and efficient garbage collection, Hermes ensures that complex React Native apps remain responsive even on resource-constrained hardware (mass-market Android devices and iOS). It is the default engine for React Native, offering seamless integration with Chrome DevTools for native-level debugging.

https://hermesengine.dev