Mattermost vs The Lounge
| Tagline | Open-source, self-hostable Slack alternative for secure team messaging and collaboration | Modern, self-hosted web IRC client for always-on team chat |
| Category | Team Chat & Collaboration | Team Chat & Collaboration |
| Replaces | Slack, Microsoft Teams, Discord | Slack |
| GitHub stars | 39k | 6.3k |
| Language | Go | TypeScript |
| License | MIT | MIT |
| Self-host difficulty | 3/5 Moderate | 2/5 Easy |
| Deploy options | One-Click Docker Docker Compose Kubernetes Manual | Docker Manual |
| Managed hosting | ||
| Last updated | 2 days ago | 5 days ago |
| View repo | View repo |
Where each falls short
The honest trade-offs — what you give up with each, versus the proprietary tools they replace.
Mattermost
- Many advanced features (LDAP/AD, SAML/SSO, compliance exports, high availability) are gated behind paid Enterprise tiers
- Search and message UX feel less polished than Slack
- Voice/video calling is more limited than Teams' full meetings stack
- Smaller third-party app/integration marketplace than Slack
The Lounge
- It is an IRC client, so you still need IRC servers/networks for actual chat
- IRC lacks native threads, rich file sharing, and message editing that Slack offers
- No built-in voice/video or app integrations
- Persistence and history depend on a connected bouncer/IRC setup
Bottom line
Choose The Lounge if you want the lower-effort setup; choose Mattermost for the larger community and ecosystem. Mattermost has seen more recent development. Open each guide below for deploy steps and the full feature gap.
Mattermost
Open-source, self-hostable Slack alternative for secure team messaging and collaboration