The Pricing Problem
Slack charges $7.25–$15/user/month per user per month. For a growing team, this adds up fast:
| Team Size | Slack Monthly Cost | Annual Cost |
|---|---|---|
| 10 people | $72 | $870 |
| 25 people | $181 | $2,175 |
| 50 people | $362 | $4,350 |
The alternative? Mattermost is Free (self-hosted). Self-hosting costs only server infrastructure — typically $5–$20/month regardless of team size.
What You Actually Get with Mattermost
Mattermost covers the core use cases that most teams actually use Slack for. Here's what you get out of the box:
- Full feature parity for 90% of common workflows
- Complete data ownership — nothing stored on third-party servers
- Setup time: ~30 mins using Docker
- Active open-source community with regular updates
- No vendor lock-in — export your data any time
The Migration Path
Switching isn't as hard as it sounds. Most teams complete a migration in a single weekend with one technical team member. The key steps:
- Export your data from Slack in their standard export format
- Set up Mattermost using the official Docker installer
- Import your data and invite your team
- Run both tools in parallel for 2 weeks before cancelling Slack