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 an open-source platform that excels in video conferencing and privacy, making it suitable for users prioritizing security. Nimbuzz, on the other hand, offers a more comprehensive communication experience with integrated messaging and calling features, catering to those seeking a versatile app for everyday communication.