Quaternion

Quaternion is a desktop instant‑messaging client that implements the Matrix communication protocol. It runs on macOS, Linux and Windows, using Qt 6.4+ for its user interface, and can be installed through native package managers, Homebrew, Flatpak or downloadable archives. The application provides the standard Matrix features such as room participation, direct messaging, and synchronization across devices, while relying on the underlying Matrix ecosystem for federation and end‑to‑end encryption.

The client is aimed at users who need a native, cross‑platform experience for Matrix without relying on web or mobile apps. It is suitable for individuals or teams that already participate in Matrix rooms and want a stable desktop environment for chat, file sharing and presence information. The project follows open‑source best practices, with source code hosted on GitHub and a public issue tracker for bug reports and security concerns.

Distinctive aspects include its use of the Qt framework to deliver a consistent UI across operating systems, packaging for many Linux distributions and Flatpak, and a Homebrew formula for macOS. Development builds are automatically published via Cloudsmith, allowing early testing of new code while the stable release remains marked as mature.