caldis/mos

Mos is a small macOS utility that makes external mouse scrolling feel smooth and natural, similar to how a trackpad feels on a MacBook. When you use a regular mouse wheel on macOS, the scrolling tends to feel choppy or abrupt compared to the fluid inertia scrolling on Apple's own trackpads. Mos intercepts the scroll wheel events from your mouse and applies interpolation, turning them into smoother, animated movements. Beyond smooth scrolling, Mos also lets you independently reverse the scroll direction for horizontal and vertical axes, so you can have natural trackpad-style scrolling vertically while keeping a different direction horizontally, for example. You can configure these settings differently per application, so a design tool might have different scrolling behavior than a browser or code editor. The app also supports mouse button remapping: you can bind mouse buttons or keyboard shortcuts to system actions like Mission Control, Space switching, screenshots, accessibility actions, running scripts, or opening files and applications. It has a dedicated "Scroll Function Key" option for temporarily switching behaviors (like turbo scrolling or direction flip) while holding a button. Logitech mice using Bolt/Unifying receivers or Bluetooth are specifically supported with additional HID protocol integration. Mos is a free, open-source menu bar application (it sits in the Mac menu bar, not as a regular window) written in Swift. It supports macOS 10.13 and later. Install it via GitHub Releases or Homebrew (brew install --cask mos). The license is CC BY-NC 4.0.