What it does
Atrium is an open-source self-hosted team chat with public/private channels, group DMs, threads, reactions, pins, saved items, search, and federation. The project describes a one-process deployment with SQLite-backed state and an optional Mac app.
Atrium focuses on a lean self-hosted chat experience. The page lists channels, group DMs, threads, reactions, search, slash commands, webhooks, and federation between servers; it also links an interactive demo and deployment guide. The code is MIT licensed. No deployment or federated server was tested.
Strengths
- Includes channels, group DMs, threads, search, and server federation.
- The vendor describes a compact one-process deployment using SQLite-backed state.
- Links an interactive demo and MIT-licensed source.
Watch out for
- Self-hosting places updates, backups, and availability on the operator.
Best for
- Small technical teams seeking self-hosted open-source chat
- Communities needing federated channels between separate servers
Sources
- Atrium — Team chat, refined. (Oct 25, 2026)