Expo is a toolchain built on React Native, open-source, and free to use. It enables developers to create native iOS and Android applications using JavaScript and React. With Expo, it is effortless to interact with the native APIs of the phone's operating system, including the camera, GPS, photo library, and others.
It also offers features like live previewing Draftbit apps during development, real-time app publishing over the air, and many more.