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 primarily focused on video conferencing and collaboration, offering robust features for group meetings, while Telegram emphasizes messaging with strong encryption and large group capabilities. Users seeking video conferencing should consider Jitsi, while those needing a versatile messaging platform may prefer Telegram.