Voltra is a React Native–focused library that enables developers to build iOS Live Activities, Dynamic Island experiences, and home screen widgets using React components. It removes the need to write Swift or SwiftUI by translating JSX into a structured representation that is rendered natively on iOS widget surfaces.

The core idea behind Voltra is to let developers define native UI surfaces using familiar React patterns while delegating actual rendering to SwiftUI on the device. JSX is converted into a compressed JSON-like structure that represents a native view hierarchy. This structure is then passed to iOS, where it is reconstructed using SwiftUI primitives.

Voltra is designed around Apple’s constraints for Live Activities and widgets, including strict payload limits and background execution rules. It supports push-based updates so that Live Activities can be updated remotely without requiring app interaction, making it suitable for real-time experiences such as delivery tracking, ride status, or event updates.

The library integrates with Expo and bare React Native projects via a config plugin that automatically sets up native extension targets. It also supports hot reload during development and provides TypeScript-first APIs for defining UI components and activity state.

Unlike traditional React Native rendering, Voltra does not run a JavaScript runtime inside widgets or Live Activities. Instead, it treats UI as a serialized blueprint that is transmitted to native code, where SwiftUI handles layout and rendering. This approach aligns with Apple’s system design constraints while enabling a React-style developer experience.

Key features include:

• Build iOS Live Activities and widgets using React Native JSX
• No Swift or SwiftUI required for UI definition
• JSX compiled into serialized SwiftUI view hierarchies
• Push-based remote updates for Live Activities
• Expo and bare React Native support via config plugin
• Hot reload for faster development iteration
• TypeScript-first APIs and structured component primitives

Common use cases include:

• Building Live Activities for real-time apps
• Creating Dynamic Island experiences
• Developing iOS widgets in React Native workflows
• Shipping server-driven UI updates
• Reducing native iOS development overhead for mobile teams

Voltra is developed by Callstack in collaboration with contributors from the React Native ecosystem, focusing on bridging React Native and Apple’s widget system.