one dev

Developing an app with One is as simple as one dev.

It takes the following arguments:

--clean    # boolean, will clear all caches before running
--host     # string, set the hostname to bind to
--port     # string, set the port to bind to
--debug    # turns on vite debugging

You can also set the port with the ONE_PORT or ONE_FORCE_PORT environment variables. See Environment Variables for details.

The One development server serves both web and native apps on the same port at the same time, and should hot reload both at once. When you see the Server running on message with a host and port, that is the same for both native and web.

Native Development

The one dev command only starts the development server — it does not build or run the native iOS/Android shell. For native development you have two options:

For quick development without custom native dependencies, install Expo Go on your device. It will auto-detect from your simulator, or press q, r in the terminal to open the app.

If you need custom native dependencies, you’ll need to build the native shell first:

1. Run one prebuild to generate the native Xcode/Android project
2. Run one run:ios or one run:android to build and launch the app

See the Build or Run the Native iOS App guide for detailed instructions.

Metro Mode

By default, One uses Vite as the native bundler. For production apps, you may want to use Metro mode which provides better stability and compatibility with React Native packages.