The challenge
Teams wanted WhatsApp-style messaging but needed data on their own server — not on third-party cloud platforms. They required groups, file sharing, and Android access, including warehouse staff who should not put company photos on a public app.
Our solution
KC LanChat runs on FastAPI with WebSocket real-time messaging, JWT auth, group chats, attachments, and Android (Kotlin Compose) and web clients. The admin can turn the service on as a Windows service on a LAN box or a small VPS you control.
- Self-hosted on LAN or VPS — messages do not leave your network unless you choose that
- Admin console and security wizard
- Read receipts and message search
- No per-user subscription fees
Rollout
We typically install on an office PC or existing server, create groups that match shifts or bays, and enrol Android phones. Training is a 20-minute floor walk, not a change-management programme. That matches how we ship other offline-first desktop tools.
Results
Sites that banned public chat for production photos still got fast coordination. IT kept a backup of the SQLite/server folder with the rest of the plant data.
What we learned
Staff will not open a second app unless it feels as fast as WhatsApp. We kept one-tap groups, large attachment buttons, and a Windows service so the chat comes back after a power cut without a technician. Android enrolment is a QR on the office TV — not an MDM-only path, though you can lock the phone later with SysLock MDM.
This is KC Softwares in Nalagarh, India — not the closed French publisher of SUMo. If your plant policy forbids public messengers for shop-floor photos, LanChat is the local alternative we actually install.