Tox

Tox is a distributed, secure messenger that brings text messaging, audio chat, and video chat together in one application. Users can move beyond standard messages when an audio or video conversation is more suitable. Its core features focus on secure communication within a distributed system, with multiple ways to hold conversations without switching between separate messaging and calling programs. Tox is for people who need secure messaging and also want built-in audio and video communication. It can serve as an open source replacement for paid products such as Slack or WhatsApp, and its source code is available under the GPL-3.0 license. A notable difference is its distributed design and open source licensing. Its stated scope is focused on messaging, audio chat, and video chat; no additional collaboration or communication features beyond those functions are identified.