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
Jitsi is a robust video conferencing solution that emphasizes ease of use and security, making it suitable for various organizations. In contrast, Xabber is an XMPP client focused on messaging and group chats, providing a user-friendly experience but lacking the extensive video features of Jitsi.