React-native-firebase

To start up a project, you use the react-native run-ios and it starts up both the simulator and the server but in cases where the app has been installed and you want to restart the server, you can stop it explicitly in the terminal and use react-native start or npm start to start it up again.

While in development version of your app the bundled version of your javascript code will be server from this webserver. If you create a release version of your app, build process of react-native will start the webserver and then it will include the this bundled version in your app.