⚖️Side-by-Side Comparison
Mattermost vs Slack: Which is Better in 2026?
We've compared 2 tools across pricing, features, ratings, and reviews to help you make an informed decision. No paid placements — just facts.
Compare different tools →| Feature | Mattermost Communication & Chat |  Slack Communication & Chat |
|---|---|---|
| Rating | No reviews yet | No reviews yet |
| Pricing | Free as of Sep 15, 2026 | Free as of Oct 3, 2026 |
| Pricing Model | Contact Sales | Freemium |
| Free Plan | ||
| Free Trial | Yes | |
| API Available | ||
| Verified | Verified | |
| Founded | 2016 | 2013 |
| HQ | Palo Alto, CA | San Francisco, CA |
| Team Size | 201-500 | 1000+ |
| Platforms | WebiOSAndroidMac+3 more | WebiOSAndroidMac+2 more |
| Top Integrations | MS TeamsAtlassianGitLabPexip+1 more | GitHub CopilotClaudeAgentforceSalesforce+8 more |
| Key Features |
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| Description | Mattermost is the open-source platform for secure, high-trust collaboration. Used by NASA, Airbus, and the US Department of Defense, Mattermost provides Slack-like collaboration with on-premises deployment for security-conscious teams. | Slack is the productivity platform where work happens. With channels, DMs, huddles, AI, and 2,000+ integrations, Slack connects 750,000+ organizations including IBM, Target, and Uber to bring teams, tools, and customers together. |