Slack vs Mattermost
Side-by-side feature comparison and pricing breakdown.
Unlimited message history Slack free plan limits to 90 days
$
✓
Self-hosted option
✗
✓
End-to-end encryption Available via plugin
✗
◉
Threaded conversations
✓
✓
File sharing
✓
✓
App/integration ecosystem Mattermost has fewer but growing integrations
✓
◉
Video/audio calls Requires plugin (e.g., Jitsi)
✓
◉
Mobile apps
✓
✓
Guest access
$
✓
Custom emoji & reactions
✓
✓
Pricing
$8.75/mo
Free Open Source
Save 100% — Save ~100% by self-hosting, or ~$0.75/user/mo vs Slack Pro with Mattermost Cloud Professional
Verdict
Mattermost is the best choice for teams that need data sovereignty, compliance, or unlimited message history without per-user cloud costs. Slack wins on polish and integrations, but Mattermost closes the gap for teams willing to self-host.
Best for: Teams wanting self-hosted messaging with full data control and compliance
Last updated: 2026-03-01