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Open source alternatives to Slack

We track 9 open-source Slack alternatives, of which 7 currently score 70 or above on Repoly's GitHub health scale and 5 ship a Docker image. Rocket.Chat leads on health at 99/100 with 547 commits in the last 90 days; across all 9 projects you are choosing between Apache-2.0, EPL-2.0, GPL-3.0 and 2 other licences.

9
Alternatives
207k
Combined stars
2,849
Commits / 90 days
5
With Docker
Licence family Licence

Showing 9 of 9 tools

All 9 Slack alternatives, ranked by health

  • Top pick · highest health

    Rocket.Chat

    99 GOOD

    Communications platform that puts data protection first (alternative to Gitter.im and Slack).

    ★ 46k · ⟳ 3 days ago · 8.8.1 · MIT

    DockerNodejsK8S
    Website ↗ Source ↗

  • Mattermost

    98 GOOD

    Platform for secure collaboration across the entire software development lifecycle, can be integrated with Gitlab (alternative to Slack).

    ★ 39k · ⟳ 3 days ago · v11.10.1 · ⊘ Proprietary

    DockerGoK8S
    Website ↗ Source ↗

  • Chatwoot

    98 GOOD

    Customer communication platform (alternative to Intercom and Zendesk).

    ★ 37k · ⟳ 3 days ago · v4.17.1 · ⊘ Proprietary

    DockerRubyK8S
    Website ↗ Source ↗

  • Huly

    98 GOOD

    All-in-one project management platform (alternative to Linear, Jira, Slack, Notion, Motion).

    ★ 28k · ⟳ 18 days ago · v0.7.426 · EPL-2.0

    DockerK8SNodejs
    Website ↗ Source ↗

  • Zulip

    88 GOOD

    Zulip is a powerful, open source group chat application.

    ★ 26k · ⟳ 3 days ago · 12.2 · Apache-2.0

    Python
    Website ↗ Source ↗

  • Element

    87 GOOD

    Fully-featured Matrix client for Web, iOS & Android.

    ★ 13k · ⟳ 3 days ago · v1.12.27 · Apache-2.0

    Nodejs
    Website ↗ Source ↗

  • Tinode

    74 GOOD

    Instant messaging platform. Backend in Go. Clients: Swift iOS, Java Android, JS webapp, scriptable command line; chatbots.

    ★ 13k · ⟳ 8 days ago · v0.25.3 · GPL-3.0

    Go
    Website ↗ Source ↗

  • Colanode

    60 SLOWING

    Collaboration suite with real-time messaging, rich text pages, file management, and dynamic databases - built for offline work (alternative to Slack, Notion).

    ★ 5.1k · ⟳ 5 months ago · v0.4.7 · Apache-2.0

    DockerK8S
    Website ↗ Source ↗

  • Virola Messenger

    10 STALE

    Instant messaging and collaboration tool with private and group chat rooms, continuous voice and video meetings, files sharing, issue tracking with integrated task board (alternative to Slack).

    ⊘ Proprietary

    C++
    Website ↗ Source ↗

Slack alternatives: common questions

What is the most maintained open source alternative to Slack?

Rocket.Chat scores highest at 99/100, with 547 commits in the last 90 days, 46k GitHub stars and its latest release (8.8.1) published 5 days ago. Element has the most raw commit activity at 663 commits in 90 days.

Which Slack alternatives use a permissive licence?

4 of 9 are permissively licensed (MIT, Apache, BSD or similar): Rocket.Chat (MIT), Zulip (Apache-2.0), Element (Apache-2.0), Colanode (Apache-2.0). 2 use copyleft licences such as GPL or AGPL, which require you to publish changes if you distribute a modified version.

Which Slack alternatives run in Docker?

5 of 9 publish a Docker image or Compose file: Rocket.Chat, Mattermost, Chatwoot, Huly, Colanode. Docker support contributes 10 of the 100 available health points, because it is the clearest signal that self-hosting is a supported path rather than an afterthought.