Best Open Source Team Chat & Messaging Tools in 2026

Real-time messaging platforms for team communication, group chats, and workplace collaboration.

5 open source team chat & messaging tools — ranked by GitHub stars. Browse all

A platform for community discussion. Free, open, simple.

The communications platform that puts data protection first.

Mattermost is an open source platform for secure collaboration across the entire software development lifecycle..

Open-source team chat with a unique topic-based threading model that makes it easy to follow multiple conversations.

Simple, open source team messaging platform