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Open source communication - custom communication systems

Communication software used to provide remote access to systems and exchange files and messages in text, audio and/or video formats between different computers or users, using their own custom protocols. 44 self-hosted custom communication systems tools are listed here, ordered purely by a repository health score that Repoly recomputes nightly. Rocket.Chat leads at 99/100 with 721 commits in the last 90 days and 46k stars, followed by Chatwoot (98) and Mattermost (98). 27 of the 44 score 70 or above, 21 publish a Docker image, and the median health is 85. MIT is the most common licence, carried by 10 of them. Between them they stand in for Slack, Zoom, WhatsApp, Zendesk and Microsoft Teams and 3 more proprietary products.

updated Oct 2026 44 tools ★ 389k stars 21 with Docker median 85

Best for…

  • Most starred

    Rocket.Chat

    46,353 stars on GitHub, the largest community in the category.

  • Most active

    One Time Secret

    4,458 commits in the last 90 days, the fastest-moving codebase here.

  • Most permissive

    Novu

    MIT licence with health 98/100: the strongest option if you need to embed or fork commercially.

Ranked by health

Table view

How the team communication tools compare

Rocket.Chat edges Chatwoot 99 to 98. Rocket.Chat also has the largest following, at 46k stars.

The most recent release is WBO v2.18.31, published yesterday. Chitchatter publishes no tagged releases, which costs up to 25 of the 100 points. Databag, PushBits and Notifo score under 40, so check recent activity before adopting them. By stack, Go (9), Nodejs (7) and C++ (5) are the most common. Rocket.Chat, Novu, ntfy and 20 more are permissively licensed; Typebot, WBO, GlobaLeaks and 11 more are copyleft. Chatwoot, Mattermost, WorkAdventure and 4 more are source-available rather than open source, which limits commercial reuse. TrueConf, GNUnet, Groupboard and 3 more are not hosted on a forge Repoly can read, so they have no measured score yet.

Communication - Custom Communication Systems: common questions

What is the best open source team communication tool?

By Repoly's GitHub health score, Rocket.Chat at 99/100 (721 commits in 90 days, 8.9.0 from 25 days ago). Chatwoot is next at 98. The score measures maintenance, not features, so shortlist the top few and try them.

Which team communication tools are the most actively developed?

One Time Secret (4,458 commits in 90 days), Tuwunel (1,066 commits in 90 days) and Zulip (808 commits in 90 days). Commit activity is 35 of the 100 health points, the largest single term.

Which team communication tools can I run in Docker?

21 of 44 publish a Docker image or Compose file, led by Rocket.Chat, Chatwoot, Mattermost, Novu, ntfy and 16 more.

Which team communication tools have a permissive licence?

23 of 44: Rocket.Chat (MIT), Novu (MIT), ntfy (Apache-2.0), Apprise (MIT), Gotify (MIT) and 18 more. 14 are copyleft.

Which paid products can open source team communication tools replace?

Slack (Rocket.Chat ranks highest here), Zoom (TrueConf ranks highest here), WhatsApp (Element ranks highest here), Zendesk (Chatwoot ranks highest here) and Microsoft Teams (Rocket.Chat ranks highest here), plus 3 more listed on the comparison pages.

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