20 self-hosted Slack alternatives

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

46k stars13.8k forkslast commit 27 Aug 2026Actively maintained

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

38.9k stars8.9k forkslast commit 26 Aug 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.

27.5k stars2.1k forksEPL-2.0last commit 11 Aug 2026Actively maintained

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

25.8k stars10.1k forksApache-2.0last commit 25 Aug 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.

19.3k stars1.4k forksAGPL-3.0last commit 26 Aug 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.

13.4k stars2.7k forksAGPL-3.0last commit 26 Aug 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 stars222 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 stars314 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.

4.6k stars587 forksAGPL-3.0last commit 26 Aug 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 stars397 forksApache-2.0last commit 22 Aug 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 stars242 forksMITlast commit 27 Aug 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 stars832 forksMPL-2.0last commit 14 Aug 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.

3.3k stars383 forkslast commit 27 Aug 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.

3.1k stars1.4k forksApache-2.0last commit 25 Aug 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 24 Aug 2026Actively maintained

Stoat (formerly Revolt) is an open-source chat platform for communities and teams with channels, direct messages, roles/permissions, moderation tools, and bot support.

2.6k stars296 forksAGPL-3.0last commit 14 Aug 2026Actively maintained

Open-source browser-based peer-to-peer chat with E2E encryption, ephemeral messages, video/audio, screen sharing, direct file transfer, and iframe embedding.

2.3k stars430 forksGPL-2.0last commit 9 Aug 2026Actively maintained

Movim is a federated social platform and web-based XMPP client for blogging, chat, communities, and real-time messaging with a responsive cross‑platform interface.

2k stars281 forksAGPL-3.0last commit 26 Aug 2026Actively maintained

RetroShare is a decentralized friend-to-friend platform for encrypted chat, mail, forums, channels and secure file sharing, with optional Tor/I2P support.

2k stars323 forkslast commit 16 Aug 2026Actively maintained

Self-hostable community discussion platform combining Q&A, forums, team chat, ideation/upvoting, and Disqus-style embedded blog comments.

1.8k stars129 forksAGPL-3.0last commit 10 Jul 2026Actively maintained