Side-by-side comparison · open source, paid tool
Mattermost vs Slack
What we have checked about each, line by line. Every value shows where it came from and when we last confirmed it.
Open Source
Mattermost
Mattermost is an open source platform for secure collaboration across the entire software development lifecycle..
Paid tool
Slack
Team messaging platform with channels, threads and app integrations.
Checked facts
Line by line
| Measure | Mattermost | Slack |
|---|---|---|
| Latest prerelease version | 12.1.0 (for 5 Nov 2026) | Not checked yet |
| Days since the last commit | 0 | Not checked yet |
| GitHub forks | 9,096 | Not checked yet |
| GitHub stars | 39,549 | Not checked yet |
| Days to a first reply on issues | 7.3 | Not checked yet |
| Open issues | 628 | Not checked yet |
| Releases in the last 90 days | 45 | Not checked yet |
A line appears only when at least one record has a value we confirmed from a source. Values we have not confirmed are left out, never guessed. Records of different types share fewer lines.
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