Open Source Objective C Runtimes

iOS-Runtime-Headers is a large collection of Objective-C header files reconstructed from Apple’s private iOS frameworks and the public runtime. Its purpose is to expose class interfaces—methods, properties, ivars, protocols—that are not documented by Apple, making it easier to explore system behavior and reverse-engineer APIs. The headers are generated by inspecting binaries and metadata, then organized by framework so developers can browse relationships and inheritance hierarchies. This is invaluable for research, debugging, and tooling where you need to understand what UIKit, Foundation, or lower-level frameworks are actually doing under the hood. The project encourages read-only exploration; code using private APIs is generally unsuitable for App Store distribution. Practitioners use it to guide experiments, prototype ideas, and inform jailbreak or internal tooling where runtime knowledge is essential.

injectionforxcode enables live code injection for iOS and macOS apps so developers can iterate on UI and logic without doing a full rebuild and relaunch. It works by compiling changed source files into dynamic bundles and loading them into the running app, swapping method implementations at runtime. The tool monitors file changes, triggers fast recompiles, and provides console feedback so you can confirm injections and quickly revert if needed. It supports Objective-C and Swift (with certain runtime caveats), and plays well with Interface Builder tweaks, letting you see visual changes almost immediately. Because it hooks into the natural development loop, it dramatically shortens feedback cycles for layout tuning, animations, and view controller logic. While not a replacement for clean rebuilds and full test runs, it’s a powerful productivity aid for day-to-day iteration.