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
FaceTime is a user-friendly video calling platform primarily for Apple users, known for its high-quality and secure connections. Jitsi, on the other hand, is an open-source solution that offers flexibility and customization, making it suitable for a wider range of devices and applications.