A mobile app is not a single thing you protect; it is a portfolio of separable assets, each governed by a different body of intellectual property law. This guide inventories every protectable layer of an app—source and object code, the API question after Google v. Oracle, the user interface and "look and feel," graphics and audio, the name and icon, novel functionality and algorithms, databases and user content, trade secrets, and third-party and open-source components—and matches each layer to the legal tool that actually reaches it. It works through the two ownership doctrines that quietly sink app companies (work made for hire versus contractor assignment), the post-Alice reality of software patents, the underused power of design patents on graphical interfaces after Samsung v. Apple, and the constraints app-store developer agreements impose above the whole stack. A running hypothetical—a fictional birdsong-identification app called Warble—keeps the abstractions concrete. The goal is a clear, priority-ordered inventory you can run on any app to decide what is worth protecting, by which regime, and in what order.