Mattermost vs Rocket.Chat
Both are alternatives to Slack. Here's how they stack up — verified facts, no spin.
Also searched as Rocket.Chat vs Mattermost — same comparison, one verdict.
Mattermost
TOP PICKSelf-hosted team chat built for security-conscious orgs.
Mattermost is an open-source, self-hostable Slack alternative with strong security and compliance features, popular with engineering and defense/regulated teams that need to own their data.
Rocket.Chat
MIT-licensed, highly customizable team communication.
Rocket.Chat is a permissively licensed (MIT) open-source communications platform you can self-host and reshape freely, with chat, voice, and omnichannel features.
Side by side
| Mattermost | Rocket.Chat | |
|---|---|---|
| Sovereignty Score | 88 | 85 |
| Open source | Yes | Yes |
| Self-hostable | Yes | Yes |
| Local-first | Yes | Yes |
| License | AGPL-3.0 | MIT |
| Pricing | Free self-host; paid Enterprise | Free self-host; paid cloud/enterprise |
Mattermost is Macrostack's recommended Slack alternative, so it's our pick here.
Mattermost
Strengths
- +Purpose-built self-hosted Slack replacement
- +Strong security/compliance story
- +Familiar channel UX
Trade-offs
- −You operate the server
- −Some features are Enterprise-only
Rocket.Chat
Strengths
- +Permissive MIT license
- +Very customizable and extensible
- +Omnichannel features
Trade-offs
- −Broad feature set can feel heavy
- −Some capabilities gated to paid tiers
More Slack head-to-heads
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Facts verified 2026-07-04. Licenses and pricing change — spotted something out of date? That's a correction we want.