Free VoIP software

privacy-focused encrypted messaging app

open source software implementing a private branch exchange for various Voice over IP protocols

Jitsi (from , "wires") is a collection of free and open-source multiplatform voice (VoIP), video conferencing and instant messaging applications for the Web platform, Windows, Linux, macOS, iOS, iPadOS, watchOS, and Android. The Jitsi project began with the Jitsi Desktop (previously known as SIP Communicator). With the growth of WebRTC, the project team focus shifted to the Jitsi Videobridge for allowing web-based multi-party video calling. Later the team added Jitsi Meet, a full video conferencing application that includes web, Android, iOS, iPadOS, and watchOS clients. Jitsi also operates me

open source instant messaging and VoIP client

free VoIP Software

Ekiga (formerly called GnomeMeeting) was a VoIP and video conferencing application for GNOME and Microsoft Windows. It was distributed as free software under the terms of the GNU GPL-2.0-or-later. It was the default VoIP client in Ubuntu until October 2009, when it was replaced by Empathy. Ekiga supports both the SIP and H.323 (based on OPAL) protocols and is fully interoperable with any other SIP compliant application and with Microsoft NetMeeting. It supports many high-quality audio and video codecs.

distributed open multimedia communications platform

instant messaging client

QuteCom (previously called WengoPhone) was a free-software SIP-compliant VoIP client developed by the QuteCom (previously OpenWengo) community under the GPL-2.0-or-later license. It allows users to speak to other users of SIP-compliant VoIP software at no cost. It also allows users to call landlines and cell phones, send SMS and make video calls. None of these functions are tied to a particular provider, allowing users to choose among any SIP provider.

Zalo is a Vietnamese instant messaging multi-platform service developed by VNG Corporation. Zalo is also used in other countries outside of Vietnam, including the United States, Japan, South Korea, Australia, Germany, Myanmar and Singapore.

Linphone (contraction of Linux phone) is a free voice over IP softphone, SIP client and service. It may be used for audio and video direct calls and calls through any VoIP softswitch or IP-PBX. Linphone also provides the possibility to exchange instant messages. It has a simple multilanguage interface based on Qt for GUI and can also be run as a console-mode application on Linux.

LinuxMCE (Linux Media Center Edition) is a free and open source software platform with a 10-foot user interface designed to allow a computer to act as a home theater PC (HTPC) for the living-room TV, personal video recorder, and home automation system. It allows control of everything in the home, from lighting and climate to surveillance cameras and home security. It also includes a full-featured VoIP-compatible phone system with support for video conferencing.

app for voice communications over VoIP protocol

Wengo was at the beginning of 2004 a subsidiary of French telecom service provider Neuf Cegetel. As of February 2012, Wengo employs 80 people in the Paris headquarters, and is a subsidiary of Vivendi. Wengo is now repositioned as an online personal and consulting services marketplace.

encrypted instant messenger app (IM)

Elastix is a unified communications server software that brings together IP PBX, email, IM, faxing and collaboration functionality. It has a Web interface and includes capabilities such as a call center software with predictive dialing.

FreeSWITCH is a free and open-source telephony software for real-time communication protocols using audio, video, text and other forms of media. The software has applications in WebRTC, voice over Internet Protocol (VoIP), video transcoding, Multipoint Control Unit (MCU) functionality and supports Session Initiation Protocol (SIP) features.

privacy preserving communication app

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Kamailio, formerly OpenSER (and sharing some common history with SIP Express Router (SER)), is an SIP server licensed under the GPL-2.0-or-later license. It can be configured to act as a SIP registrar, proxy or redirect server, and features presence support, RADIUS/syslog accounting and authorization, XML-RPC and JSON-RPC-based remote control, SQL and NoSQL backends, IMS/VoLTE extensions and others.

H.323 gatekeeper implementation

trixbox (formerly Asterisk@Home) was a software PBX based on Asterisk.