Team Communication & Collaboration Tools
5 open source team communication platforms you can self-host. Compare Slack, Microsoft Teams, and Zoom alternatives by chat, calls, and license. Updated Sept 2026.
Zulip
Zulip is an open-source team chat application, and a self-hosted alternative to Slack. Its distinguishing feature is topic-based threading: every message in a channel belongs to a named topic, so conversations stay separable and catch-up reading is fast even in busy channels. It offers full-text search, hundreds of integrations, interactive bots, and native mobile and desktop apps.
Jitsi Meet
Jitsi Meet is an open-source video conferencing platform, and a self-hosted alternative to Zoom, Google Meet, and Microsoft Teams. Meetings run in the browser over WebRTC with no account or install for participants, and scale from peer-to-peer calls to large moderated rooms via the Jitsi Videobridge. The whole stack is self-hostable, so meeting media and metadata stay on your servers.
Mattermost
An open source platform for secure collaboration across the software development lifecycle, enabling teams to communicate, coordinate, and manage projects efficiently.
Rocket.Chat
An open-source communication platform enabling secure, real-time conversations for organizations, supporting team collaboration, customer service, and flexible deployment across various channels.