Expo
A toolkit that helps you build, preview, and ship React Native apps without managing all the plumbing yourself.
Think of moving into a furnished apartment instead of buying every fixture. Expo gives you a ready setup to develop and ship a React Native app.
It provides tools to start the app on your phone during development, handle common device features, and build installers for the stores. This saves setup time, which is often fiddly.
In practice you run a local server that shows a QR code, scan it with the Expo app on your phone, and see changes live. When ready, you use Expo’s build services to produce the files you submit to Apple and Google.