Mattermostmattermost/mattermostalivereplaces both
- GitHub
- ★ 36.7k · last commit today
- License
AGPL-3.0- Setup time
- 20min docker-compose (Go server + Postgres)
- Monthly cost
- $10/mo VPS for a 50-user team; Postgres is the heaviest piece.
Microsoft Teams vs Slack
Self-host either: open-source alternatives compared. · Category: team chat & community
Both Microsoft Teams and Slack are in the team chat & community category. 2 open-source projects (Mattermost, Rocket.Chat) self-host as a replacement for both — listed below alongside the picks unique to each.
| Microsoft Teams | Slack | |
|---|---|---|
| Category | Team chat + video meetings | Team chat |
| SaaS pricing anchor | Teams Essentials $4/user/mo; bundled in M365 Business Basic at $6/user/mo | $8.75/user/mo on Pro; message history capped on free tier |
| Self-host options listed | 3 | 3 |
Replaces both — 2 shared open-source picks
These open-source projects appear on both /microsoft-teams/ and /slack/ — picking one solves the migration off either SaaS.
Rocket.ChatRocketChat/Rocket.Chatalivereplaces both
- GitHub
- ★ 45.3k · last commit today
- License
MIT- Setup time
- 20min docker-compose (Node + MongoDB)
- Monthly cost
- $10/mo VPS; MongoDB needs RAM and growing index space.
Picks unique to each
In a terminal? npx os-alt microsoft-teams or npx os-alt slack prints either side —
how the CLI works →
FAQ
Which open-source self-host alternatives replace both Microsoft Teams and Slack?
2 open-source projects appear on both /microsoft-teams/ and /slack/: Mattermost, Rocket.Chat.
How many self-host alternatives are listed for Microsoft Teams and Slack?
3 for Microsoft Teams, 3 for Slack.
Are all the self-host alternatives free?
Yes — every listed option is open source. Your cost is the VPS or hardware that runs it.