Free

Telegram is a free cloud-based instant messaging platform.

Mumble

Open Source

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

TeamSpeak

Freemium

TeamSpeak is software for quality voice communication via the Internet.

Mattermost

Open Source

Mattermost is an open source, private cloud Slack-alternative, Workplace messaging for web, PCs and phones. MIT-licensed.

Ring

Open Source

Ring (SFLphone) is an open-source SIP-compatible softphone and instant messenger for Linux, Microsoft Windows, OS X and Android.

Overwolf

Free

Overwolf is a software platform which allows developers to create extensions (called applications by Overwolf Ltd.) for video games.

TribeScale

Free

TribeScale is an All-in-One platform to coordinate your team around what really matters - communication, goals, decisions, tasks and results.

Flock

Freemium

Flock is a communication app for teams. Packed with tons of productivity features, Flock drives efficiency and boosts speed of execution.

Zulip

Open Source

Zulip is a chat and collaborative software.

Wickr

Free

Wickr is an instant messenger application.

Slack

Freemium

Slack is a cloud-based team collaboration tool.

Tox

Open Source

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

RetroShare

Open Source

RetroShare is open source software for encrypted filesharing, serverless email, instant messaging, online chat, and BBS, based on a friend-to-friend network b…

Wire

Free

Wire is a cross-platform, encrypted instant messaging client created by Wire Swiss. It is available for iOS, Android, Linux, Windows, macOS and Web browser cl…

Ventrilo

Free

Ventrilo (Vent) is a VoIP software that includes text chat.

Matrix.org

Open Source

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…