Matrix is an open protocol for real-time communication. It is designed to allow users with accounts at one communications service provider to communicate with users of a different service provider via online chat, Voice over IP, and Videotelephony. Developed by Matrix.org
License: Open Source
Matrix.org offers a decentralized, feature-rich messaging platform with strong security features, while Pidgin is a lightweight, versatile chat client that excels in supporting multiple protocols but lacks advanced features like voice and video calls.