Home / Compare / Mattermost vs Slack

Mattermost vs Slack (2026)

Side-by-side comparison of Mattermost and Slack on BizOps Score, pricing, GitHub health, and self-hosting. Updated 2026-05-30.

🏆 WINNER
76
Mattermost
Communication
Open Source
Price: Free (self-hosted)
Stars: 28,000
View on GitHub →
vs
—
Slack
Communication
Paid
Price: $7-$12/user/mo
Stars: N/A (paid)
Visit website →
💡 Verdict: Mattermost wins (BizOps Score 76/100)

Mattermost is open-source and free to self-host. Slack is a paid proprietary tool. For teams prioritising cost and data ownership, Mattermost is the clear choice. Use our Stack Grader for a personalised recommendation.

Feature comparison
MetricMattermostSlack
BizOps Score76/100N/A/100
LicenseOpen SourceProprietary
GitHub Stars28,000N/A (paid)
Monthly CostFree (self-hosted)$7-$12/user/mo
Self-hosting✓ Available✗ Cloud only
CategoryCommunicationCommunication
Choose Mattermost when…
  • You want full data ownership and self-hosted control
  • Cost reduction is a priority — Mattermost is free to self-host
  • Your team has technical capacity to deploy and maintain
GitHub →
Choose Slack when…
  • You need enterprise support and guaranteed SLA
  • Integration with existing enterprise stack is critical
  • Your team prefers clicking over coding
Website →
Not sure which fits your stack?

Our free AI Stack Grader analyses your full tool stack and recommends the best open-source alternatives.

Grade my stack free → Browse all alternatives →