Slack vs Mattermost
A side-by-side look at Slack (the paid SaaS) and Mattermost (the open source alternative). Use this page to decide if the switch fits your team and workflow.
| Slack | Mattermost | |
|---|---|---|
| Tagline | Team messaging with channels, threads, and integrations. | Slack-style open source team messaging. |
| License | Proprietary SaaS | AGPL-3.0 / Apache-2.0 (modules) |
| Pricing | Free tier limited to 90 days of history; Pro from $7.25/user/month. | Free to self-host · optional paid hosted plan |
| Self-host option | No | Yes — difficulty 3/5 |
| Hosted cloud available | Yes (only option) | Yes |
| Desktop apps | Varies by product | Windows, macOS, Linux |
| Mobile apps | Official apps typically available | iOS, Android |
Best for
The most drop-in Slack replacement for teams.
Mattermost strengths
- Familiar Slack-like UX.
- Strong self-hosting story and enterprise features.
- Good permission and compliance controls.
Mattermost weaknesses
- Some advanced features require paid tier.
- Mobile app performance is acceptable but not stellar.
- Larger install footprint than lightweight chats.
What's the catch with Slack?
- Free tier message history cap makes it unusable for serious teams.
- Data residency concerns for EU and regulated industries.
- Per-seat pricing scales expensively.
Still unsure?
Check the full list of alternatives to Slack: see Slack alternatives, or learn more about Mattermost on its project page.
Recommended reading
Why your team probably can't ditch Slack yet (and what needs to change)
Mattermost and Rocket.Chat are excellent. So why do most teams who try to migrate away from Slack end up back on Slack? An honest look at the real blockers.
When self-hosting goes wrong: seven failure modes and how to avoid them
An honest retrospective on the ways self-hosted setups break — not in theory, but in practice — and the small habits that prevent most of them.
Will the open source project you depend on still exist in three years?
Bus factor, maintainer burnout, funding models, and the signals that separate OSS projects that survive from those that quietly decay.