Caffeine

Caffeine is a lightweight menu-bar utility for macOS that prevents your Mac from automatically sleeping, dimming the screen, or starting screen savers while you are working or presenting. It sits unobtrusively in the menu bar and can be toggled on or off with a single click. Power users, presenters, and anyone who needs to keep their machine awake without diving into System Settings rely on Caffeine for its simplicity and minimal resource footprint. The app includes a timer function to automatically re-enable sleep after a set number of minutes.