The Door POS app can keep checking patrons in even when the venue has no internet — no live connection to Noctern is needed to scan a ticket or reprint one.
Before doors: the app downloads a full ticket list
When staff sign in for an event, the app downloads a complete list of every ticket for that performance — the same QR code the scanner checks, each patron's name and seat/section, the ticket's current status, and a ready-to-print ticket layout for reprints. This download happens once, while the venue network is still up, so the device has everything it needs for the rest of the night even if connectivity drops the moment doors open.
Because the reprint layout is already on the device, reprinting a lost or damaged ticket at the door never needs a live connection either — the app sends the stored layout straight to the printer.
The app refreshes this list periodically while online. If nothing has changed since the last download, the refresh is a cheap no-op — Noctern tells the app "nothing's different" instead of resending the whole list.
While offline: scans are queued, not lost
Every scan is recorded on the device the moment it happens, whether or not the app can reach Noctern. Nothing is held back waiting for a connection.
Back online: scans sync automatically and safely
Once the device reconnects, it uploads every queued scan in the background. This sync is safe to run more than once — if the same scan gets uploaded twice (a retry after a dropped connection, for example), Noctern recognizes it and does not double-count it.
If the same ticket was scanned on two different devices while both were offline (a guest slips past one door and tries another), Noctern keeps the earliest scan as the official check-in time once both devices sync. The second, later scan is recorded as a duplicate for the door report — it does not un-check-in the guest or create a second valid entry.
What shows up in the attendee report afterward
A ticket checked in while the device was offline is marked in the event's attendee list with "Scanned offline" and the time it actually synced back to Noctern — useful for reconciling what happened at the door after a rough connectivity night. The attendee list also shows a running count of duplicate scans — the same ticket scanned more than once across devices — so you can spot a guest list issue or a gate that needs tighter control next time.
After an event with connectivity trouble, open AdminEvents[event]Attendees and check the duplicate-scan count near the top of the list.