Karabiner

Karabiner is an open‑source utility that lets macOS users remap and modify keyboard behavior. It provides a framework for defining custom key bindings, complex modifications, and device‑specific configurations, allowing users to tailor the input experience to their workflow. The software runs as a background service, applying the defined rules system‑wide and supporting a wide range of keyboards.

Its design emphasizes stability, offering a reliable platform that works across macOS releases without requiring additional drivers. Because it is freely available under an open‑source license, users can inspect, modify, and share configuration files, and the project maintains a free tier that includes the core functionality needed for most customization tasks.

Karabiner is suited for developers, power users, and anyone who needs precise control over key mapping on macOS. Its extensible rule system and community‑driven development make it a practical choice for adapting the keyboard to specific applications, ergonomic preferences, or accessibility requirements.