Jitsi (formerly SIP Communicator) is a free and open source multiplatform voice (VoIP), videoconferencing and instant messaging application. Developed by University of Strasbourg (France), plus many others.
License: Open Source
Fring is a user-friendly platform ideal for quick communication with good audio and video quality but lacks some advanced features like screen sharing. In contrast, Jitsi is an open-source solution that offers high customizability and strong security features, making it better suited for tech-savvy users or those needing more control over their communication tools.