Mouser: An open source alternative to Logi-Plus mouse software
A lightweight, local tool that remaps all 6 programmable buttons on Logitech's flagship mouse without requiring any Logitech software.
Developer TomBadash has released Mouser, a lightweight, open-source alternative to Logitech's proprietary Options+ software specifically for the Logitech MX Master 3S mouse. The tool communicates directly with the mouse using the HID++ 4.5 protocol over Bluetooth, allowing users to remap all six programmable buttons—including the middle click, gesture button, and horizontal scroll—without any Logitech software running. It features a modern Qt Quick UI with a dark Material theme and an interactive mouse diagram for intuitive configuration. All processing happens locally, with settings stored in a JSON file, ensuring zero telemetry and no cloud dependency.
Mouser offers advanced functionality like per-application profiles that automatically switch button mappings when users change apps (e.g., different bindings for Chrome versus VS Code). It includes 22 built-in actions across navigation, browser, editing, and media categories, such as Alt+Tab, browser back/forward, copy/paste, and media controls. The software also provides DPI/pointer speed control with a slider from 200 to 8000 DPI, scroll direction inversion, and live connection status. For macOS users, full compatibility has been added using CGEventTap for mouse hooking and Quartz CGEvent for key simulation, though the primary development is for Windows 10/11.
The architecture is designed to be extensible to other Logitech HID++ mice, though only the MX Master 3S (Product ID 0xB034) is currently tested. Users can download a 44MB ZIP file, extract it, and run the executable immediately—no installation required. The app runs in the system tray, maintains remapping in the background, and automatically reconnects if the mouse is turned off and on. This project represents a significant move toward user sovereignty in peripheral customization, freeing a popular productivity mouse from vendor-locked software.
- Remaps all 6 programmable buttons on the Logitech MX Master 3S with 22 built-in actions across navigation, browser, editing, and media categories.
- Offers per-application profiles for automatic button mapping switching and DPI control from 200-8000, all processed locally with zero telemetry or cloud services.
- 44MB executable requires no installation, runs on Windows 10/11 and macOS 12+, and uses HID++ 4.5 protocol to bypass Logitech Options+ entirely.
Why It Matters
Gives power users full control over premium hardware without mandatory vendor software, telemetry, or cloud accounts, setting a precedent for open-source peripheral tools.