Open source · AGPL-3.0 source / MIT compiled Linux Self-hostable
Self-host
Runs on your own Linux server. Setup docs are on mattermost.com.
Free alternatives to Slack
Swap Slack for Mattermost, Rocket.Chat or Zulip and stop paying $87/yr.
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Prices and project data checked · How we check
$87/yr Pro Verified on slack.com, Oct 17, 2026
3 alternatives
Open source · MIT Linux Self-hostable
Self-host
Runs on your own Linux server, with Docker files in the repo. Setup docs are on rocket.chat.
Open source · Apache-2.0 Linux Self-hostable
Self-host
Runs on your own Linux server, with Docker files in the repo. Setup docs are on zulip.com.
At a glance
| Alternative | License | Linux | AUR | Self-host | Stars |
|---|---|---|---|---|---|
| Mattermost | AGPL-3.0 source / MIT compiled open source | Yes | — | Yes | 39.4k★ |
| Rocket.Chat | MIT open source | Yes | — | Yes | 46.3k★ |
| Zulip | Apache-2.0 open source | Yes | — | Yes | 26.0k★ |
Slack alternatives: questions
- Is there a free alternative to Slack?
- Yes. The 3 free alternatives are Mattermost (open source, AGPL-3.0 source / MIT compiled), Rocket.Chat (open source, MIT) and Zulip (open source, Apache-2.0).
- How much does Slack cost?
- Slack's Pro plan costs $7.25 a month, which is $87 a year (per user, paying annually ($8.75 monthly)). Source: the official pricing page at slack.com, checked Oct 17, 2026.
- Which Slack alternatives run on Linux?
- Mattermost (self-hosted server; web UI), Rocket.Chat (self-hosted server; web UI) and Zulip (self-hosted server; web UI).
- Can you self-host a Slack alternative?
- Yes. Mattermost, Rocket.Chat and Zulip run on your own server.
- Are these Slack alternatives open source?
- Yes. All 3 use OSI-approved open-source licenses: Mattermost (AGPL-3.0 source / MIT compiled), Rocket.Chat (MIT) and Zulip (Apache-2.0).
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