Jitsi

The world’s best video conferences are built on Jitsi. Jitsi is a set of open-source projects that allows you to easily build and deploy secure videoconferencing solutions. At the heart of Jitsi are J...
Language(s): Java
Operating system(s): Linux, Mac OS X, Windows
License: Apache License 2.0

QuteCom

QuteCom (previously called WengoPhone) is a free-software SIP-compliant VoIP client developed by the QuteCom (previously OpenWengo) community under the GNU General Public License (GPL). It allows user...
Language(s): C, C++, Qt
Operating system(s): Cross-platform
License: GNU General Public License

Signal

Signal is a cross-platform encrypted messaging service developed by the Signal Foundation and Signal Messenger LLC. It uses the Internet to send one-to-one and group messages, which can include files,...
Language(s): N/A
Operating system(s): Android 4.4 or later, iOS 9.0 or later, Windows 7 or later (64-bit), Mac OS 10.9 or later,] Linux distributions
License: Clients: GPLv3, Server: AGPLv3

Tox

Whether it's corporations or governments, digital surveillance today is widespread. Tox is easy-to-use software that connects you with friends and family without anyone else listening in. While other ...
Language(s): C
Operating system(s): Windows, Linux, OS X, Android, iOS, FreeBSD, OpenIndiana, Sailfish OS
License: GNU General Public License v3

Twinkle

Twinkle is a free and open-source app for voice communications over Voice over IP (VoIP) protocol. It is designed for Linux operating systems and uses the Qt toolkit for its graphical user interface. ...
Language(s): C++
Operating system(s): Linux
License: GNU General Public License