Mattermost

Open-source, self-hosted Slack alternative for team messaging

Open Source

Free self-hosted, $10/user/mo cloud Professional

self-hosted open-source chat enterprise

About Mattermost

Mattermost is an open-source messaging platform that offers a self-hosted alternative to Slack. It provides unlimited message history, full data control, and enterprise features without per-user cloud pricing. Ideal for teams that need security, compliance, or want to avoid vendor lock-in.

Highlights

✓ Self-hosted with full data control
✓ Unlimited message history on all plans
✓ Open-source with active community
✓ DevOps integrations (Jira, GitLab, Jenkins)

Limitations

✗ No built-in video calls (requires plugin)
✗ Self-hosting requires server maintenance
✗ Smaller app ecosystem than Slack

Replaces

Slack Free tier

View alternatives →

Detailed Comparisons

Slack vs Mattermost →

Free

Free self-hosted, $10/user/mo cloud Professional

Visit Mattermost →

Last updated: 2026-03-01