flextool/flex

FLEX, short for Flipboard Explorer, is a set of debugging and exploration tools that you bundle into your own iOS app while developing it. When you turn it on, FLEX shows a small toolbar floating in a window above your running app. From there, an iOS developer can peek into and change almost every piece of internal state in the app without rebuilding or attaching a separate debugger. The README lists a long set of things you can do once it is active. You can pick a view and look at its properties and instance variables, then change them on the fly. You can call methods on any object. You can browse the network history with timings, headers, and full responses, view NSLog messages, and edit NSUserDefaults. You can also scan the heap for live objects, walk the app's sandbox file system, and open SQLite or Realm database files inside it. A key point in the README is that FLEX runs entirely inside the app itself. You do not need to be connected to LLDB or Xcode or any remote debugging server, and it works both in the simulator and on a real device. In the simulator, pressing f toggles the toolbar and pressing ? lists the keyboard shortcuts. You can also start it from code, with a one-liner in Objective-C or Swift, often guarded by a #if DEBUG block or wired to a gesture like a six-finger quadruple tap. The feature sections give more detail. The network history can be set to start automatically at launch, and there are limits you can set on cached response bodies. The heap view uses malloc to find live allocated blocks that look like objects. There is an explore-at-address feature that opens an arbitrary pointer, with a warning and an unsafe option if FLEX is not sure the pointer is valid. The file browser pretty-prints JSON and plist files, shows image previews, and lets you rename, delete, or share files. The library explorer lets you dig through all loaded public and private classes. The README notes that tvOS is not supported out of the box but points to a community fork. A small section called Learning from Other Apps mentions code injection, with the technique left as an exercise for the reader.