LSPatch

LSPatch is an open‑source runtime patching library developed for iOS applications. Designed to simplify the process of modifying app behavior without altering the original binary, it exploits Objective‑C's dynamic nature to inject custom code at launch. The library supplies a small, self‑contained compiled framework that developers embed into their projects. When the host application starts, LSPatch loads its framework and, using the runtime API, applies a series of specified patches. These patches can replace or augment methods, alter class hierarchies, or add functionality to existing objects. Because the changes occur at runtime, the underlying app code remains untouched, making LSPatch useful for rapid prototyping, hot‑fix releases, or educational demonstrations of runtime manipulation.

LSPatch originated from the community of iOS developers who required a lightweight, reliable patching mechanism for personal or collaborative projects. The project is available under an MIT style license, allowing free usage, modification, and distribution. While it can be used for benign purposes such as customizing UI components or debugging, LSPatch can also facilitate unauthorized modifications. Consequently, many app stores ban or flag applications that rely on LSPatch, and using it to circumvent security controls or to crack apps is illegal and discouraged.

Typical use cases include patching third‑party libraries to fix bugs, injecting analytics code, or enabling feature toggles without a full rebuild. To employ LSPatch, developers create a configuration file mapping selectors to replacement implementations, bundle the LSPatch framework with their app, and build the project. At runtime, the framework automatically applies the patches before the app’s main logic begins. LSPatch demonstrates how dynamic languages can extend software behavior in flexible, though potentially risky, ways.