Business Instant Messaging · head-to-head
Mattermost vs Slack
The written short answer is being updated after a re-evaluation. The scores below are current.
Read this comparison as one judge. Each weighs the same scores by what they care about.
The bench's picks
Same scores, different priorities: each judge's weighting applied to both products. The split is the finding.
- The Team Lead Mattermost Slack picks Mattermost
- The Security Officer Mattermost Slack picks Mattermost
- The Works Council Advocate Mattermost Slack picks Mattermost
- The Compliance Counsel Mattermost Slack picks Mattermost
- The Platform Engineer Mattermost Slack picks Mattermost
- The Skeptic Mattermost Slack picks Mattermost
Criterion by criterion
| Criterion | Mattermost | Slack | The bench leans |
|---|---|---|---|
| Channels, threads & search | Slack, 3 of 6 judges | ||
| Encryption & access control | Mattermost, 2 of 6 judges | ||
| Retention, discovery & co-determination | Mattermost, 6 of 6 judges | ||
| Deployment & data custody | Mattermost, 6 of 6 judges | ||
| Integrations & extensibility | Mattermost, 3 of 6 judges | ||
| European sovereignty | split 2–2 | ||
| Pricing transparency | no published price | not comparable |
Stars show the bench average per criterion; the lean counts which product each judge scored higher. Open a judge's tab for their reasoning on both sides.
Sovereignty, side by side
| Dimension | Mattermost | Slack |
|---|---|---|
| Legal entity | Not determined | Not determined |
| Ownership | Not determined | Not determined |
| Data residency | Not determined | Not determined |
| Subprocessors | US CLOUD Act reach | Not determined |
Facts, side by side
Only facts both products carry under the same definition — anything else would not be a fair row.