Main Page: https://chatto.run/
Git: https://github.com/chattocorp/chatto
Licence: AGPL-3.0-or-later (shared framework modules, standalone frontend, docs and examples are Apache-2.0; the bundled Runling orchestrator is MIT)
Dockerfile: Yes – official image plus a Docker Compose example (https://github.com/chattocorp/chatto/tree/main/examples/dockercompose)
Demo: Official Chatto Community (a live instance run by the developers): https://chat.chatto.run/
Summary: Chatto is a fast, fully-featured, web-based team and community chat app that you can self-host for free. Think Slack/Teams/Discord, but tiny: it ships as a single ~50–70 MB Go binary with no separate database required (data lives in an embedded NATS JetStream store, or an external NATS server for scaling).
Features include rooms, threads, replies, DMs, notifications and Web Push, full-text search, file attachments (with thumbnails, GIF processing and ffmpeg video transcoding), voice and video calls with screen sharing (via LiveKit), flexible roles and permissions with room groups as permission boundaries, SSO via external login providers (e.g. Pocket ID), S3-compatible storage for media, an admin dashboard, operator CLI, and backup/restore tooling. It also exposes GraphQL/ConnectRPC and NATS APIs for bots and integrations.
Privacy is a core focus: message text and selected account fields are encrypted at rest with per-user keys, and crypto-shredding is supported on account deletion. It's made in Germany and positioned as GDPR-ready. Each deployment is one isolated community — no federation by design.
Notes:
Why I like it: A genuinely lightweight alternative to Slack / Discord / Mattermost / Rocket.Chat that still covers the essentials, including built-in calls and screen sharing. Single binary with an embedded data store should map nicely onto Cloudron's /app/data model, and SSO support means it could hook into Cloudron's OIDC login. Active development (0.4.0 released, ~2.8k GitHub stars).
Packaging considerations:
Voice/video needs LiveKit, which wants its own hostname plus TCP 7881 and UDP 3478 / 50000–50200. Calls could be optional in a first version, or LiveKit could perhaps use Cloudron's TURN addon.
Direct email/password registration requires SMTP (Cloudron's sendmail addon should cover this).
Push notifications need VAPID keys, which could be generated on first run.
Runs as non-root (UID 1000) by default.
Concerns:
Still 0.x – the docs say to expect bugs, missing features, frequent upgrades and unannounced breaking API changes.
The project doesn't accept outside contributions at this time.
It's openly built with the help of AI coding agents, which some users may want to know.
Developer contact: Chatto is developed by Hendrik Mans in Germany. I can connect.
Alternative to / Libhunt link: Slack, Microsoft Teams, Discord, Mattermost, Rocket.Chat (no Libhunt listing yet)
Screenshots:
Light: https://docs.chatto.run/_astro/chatto_light.DjfyysJr_Z2cNdhj.webp
Dark: https://docs.chatto.run/_astro/chatto_dark.ku0fA5mZ_Z1SQ7CW.webp
Hero: https://chatto.run/_app/immutable/assets/chatto.CJP_M7Vp.webp
Logo: https://github.com/chattocorp/chatto/blob/main/favicon.png