KeyCastr displays keyboard and mouse input on screen in real-time, providing visual keystroke feedback during presentations, screencasts, and technical demonstrations. The open-source app addresses the challenge of communicating keyboard shortcuts to audiences who cannot see physical key presses.
The app runs from the menu bar and displays an overlay in a configurable screen corner showing pressed keys. Configuration options include displaying command keys only, all modified keys, or complete keystroke logging. The overlay is repositionable via click-and-drag, defaulting to the bottom left corner. Optional mouse click visualization shows physical interactions alongside keyboard input.
Privacy implementation includes no networking code beyond the standard Sparkle update framework. The app avoids capturing password fields when websites use secure input methods. The project is licensed under BSD 3-Clause with the entire codebase available on GitHub, where it has accumulated over 14,500 stars.
Performance impact is negligible with no observable lag during intensive screen recording sessions. The overlay renders smoothly without interfering with other applications. Visual styling prioritizes clarity and readability over aesthetic flourish.
Installation options include direct download from GitHub releases or Homebrew via brew install --cask keycastr. On macOS 10.15 Catalina and newer, Input Monitoring or Accessibility permissions are required through System Preferences.
The project has been maintained since 2009 with 22 contributors and responsive developer engagement on GitHub issues. The codebase is written in Objective-C with documentation for custom visualizer contributions.
Limitations include functional rather than highly customizable visual styling and the standard permission requirements for keyboard monitoring applications.
Alternatives include commercial options like Keystroke Pro that offer additional visual customization.
Suitable for users who create technical tutorials, conduct remote training sessions, produce screencast content, or regularly share screens during demonstrations where keyboard shortcut visibility improves audience comprehension.
