20 self-hosted Microsoft Teams alternatives

Rocket.Chat is an open-source communications platform for secure team messaging, channels, DMs, voice/video, integrations, and customer omnichannel support.

45.9k stars13.8k forkslast commit 28 Jul 2026Actively maintained

Open-source, self-hosted messaging platform for secure team collaboration with real-time chat, audio calls, screen sharing, and integrations.

38.6k stars8.9k forkslast commit 28 Jul 2026Actively maintained

Nextcloud is an open-source content collaboration platform providing file sync & share, groupware (calendar, contacts, mail), real-time office editing, chat and video conferencing.

36.3k stars5.1k forksAGPL-3.0last commit 28 Jul 2026Actively maintained

Self-hostable WebRTC video conferencing with chat, screen sharing, moderation tools, and SDKs for embedding meetings into web and mobile apps.

29.7k stars8k forksApache-2.0last commit 23 Jul 2026Actively maintained

Huly is an open-source all-in-one platform combining project management, team chat, and collaborative documentation as an alternative to tools like Jira, Linear, Slack, and Notion.

27.1k stars2.1k forksEPL-2.0last commit 27 Jul 2026Actively maintained

Open-source team chat server with topic-based threading for focused, asynchronous, and real-time communication in distributed teams.

25.6k stars10k forksApache-2.0last commit 27 Jul 2026Actively maintained

Open-source, decentralized messaging network built on a Haskell core with Kotlin Multiplatform and native iOS clients; end-to-end encrypted messaging without user IDs.

19.1k stars1.2k forksAGPL-3.0last commit 3 Jul 2026Actively maintained

Element is a Matrix client for secure team messaging and collaboration, offering end-to-end encrypted chats and calls with interoperability across the Matrix network.

13.3k stars2.7k forksAGPL-3.0last commit 27 Jul 2026Actively maintained

Open-source screen sharing server that runs self-hosted; WebRTC-based with TURN server; Docker or single-binary deployment; browser-based.

10.5k stars717 forksGPL-3.0last commit 13 May 2026Actively maintained

BigBlueButton is an open-source virtual classroom and web conferencing platform with real-time audio/video, screen sharing, whiteboards, breakout rooms, polling, and recordings.

9.2k stars6k forksLGPL-3.0last commit 27 Jul 2026Actively maintained

Spacebar is an open source, self-hostable Discord-compatible communication platform with text chat, voice, and video, designed to work with existing clients and bots.

6.7k stars223 forksAGPL-3.0last commit 9 Apr 2026Actively maintained

Open-source, local-first Slack and Notion alternative combining team chat, rich docs, databases, and file management with offline-first sync and self-hosting.

5k stars308 forksApache-2.0last commit 3 Apr 2026Actively maintained

Synapse is a Matrix homeserver implementation for running federated, secure real-time chat and collaboration on your own infrastructure.

4.5k stars571 forksAGPL-3.0last commit 27 Jul 2026Actively maintained

Tailchat is an open source team chat and collaboration platform with a strong plugin system, bot integrations, multi-group workspaces, and RBAC permissions.

3.6k stars394 forksApache-2.0last commit 20 Jul 2026Actively maintained

Converse.js is an open-source, client-side web XMPP/Jabber chat app that can run standalone or be embedded into sites, with group chat and OMEMO encryption.

3.3k stars833 forksMPL-2.0last commit 24 Jul 2026Actively maintained

Ergo is a modern IRC server (ircd) written in Go, with integrated account management, history storage, bouncer-like features, and strong IRCv3 support.

3.3k stars236 forksMITlast commit 22 Jul 2026Actively maintained

Stoat is an open-source, self-hostable chat platform for communities and teams, offering text channels, permissions, moderation tools, and a web app.

3.2k stars369 forkslast commit 22 Jul 2026Actively maintained

An open-source WebRTC SFU that routes media for scalable multiparty video conferencing; supports Colibri XMPP/REST control, DTLS/SRTP, and Prometheus metrics.

3.1k stars1k forksApache-2.0last commit 16 Jul 2026Actively maintained

Openfire is an open source XMPP (Jabber) server for real-time messaging and collaboration, with a web admin console and a plugin ecosystem.

3k stars1.4k forksApache-2.0last commit 24 Jul 2026Actively maintained

Tox is a decentralized, peer-to-peer communication system for encrypted messaging, voice/video calls, screen sharing, and file transfers without central servers.

2.7k stars311 forksGPL-3.0last commit 20 Jun 2026Actively maintained