The difference between alpha vs beta apps, and nightly vs production builds, lies in their purpose and position in the mobile app development cycle. A build is the compiled source code of an app, while alpha, beta, nightly, and production builds represent different stages of testing and iteration. Alpha builds are initial working versions with missing features, beta builds mark the completion of development and focus on quality and usability, nightly builds reflect daily changes and can be buggy, and production builds are stable and ready for distribution to end-users. The process involves iterative testing and feedback loops, with each build serving a specific purpose in the development cycle.