Mumble is an open source, low-latency, high quality voice chat software primarily intended for use while gaming.

TeamSpeak is software for quality voice communication via the Internet.

UserEngage is a Real-Time Customer and User Engagement Tool for Big and for Small Businesses, designed for maximizing the conversion.

Tox is a peer-to-peer instant-messaging and video-calling protocol that offers end-to-end encryption.

Matrix is an open protocol for real-time communication. It is designed to allow users with accounts at one communications service provider to communicate with…

Coccinella is a free and open-source cross-platform client for the XMPP/Jabber-instant messaging-protocol.