Keycastr is a system-level utility for macOS that captures and displays keyboard and mouse interactions as visual overlays on the desktop. By registering global event taps within the operating system, it monitors input actions in real time and renders them through transparent, non-interactive windows that float above other active applications.
The application distinguishes itself through a plugin-based architecture that allows for the integration of custom modules to define how input events are rendered. Users can manage the lifecycle and positioning of these visual elements through a native interface, enabling the drag-and-drop placement of overlays and the selection of specific keystrokes or mouse clicks to be displayed during live sessions or recorded demonstrations.
The software provides a comprehensive set of tools for customizing the visual output, including options to filter which keys appear and to extend the core visualization logic. It is designed to support instructional clarity and accessibility by making hidden input actions visible during screen sharing, presentations, and the production of educational video content.
