Designing an offline-first check-in

Visitor management is a physical security control. It cannot depend on a cloud service being reachable at the moment a contractor arrives.

LAN-first by default

The primary deployment is a mini-PC on site. Tablets and phones talk to the web gateway over local Wi-Fi. The API, the database and the ID images all live on the same local network.

Queue instead of fail

SMS and cloud OCR queue until connectivity returns. Local OCR takes over immediately. Check-in and check-out queue on the device and retry automatically, with a visible LOCAL MODE banner showing the pending count.

Make the state obvious

Operators need to know whether they are online, whether the queue is growing, and whether the last scan was written. A quiet fallback is worse than a loud one.