Yes. The check-in app syncs in real time with all other devices logged into the same event. This allows multiple staff members to check in guests simultaneously from different entry points.
Syncing requires a Wi-Fi or mobile data connection. If your device goes offline, the app continues working and stores check-in data locally. When the connection is restored, all queued data syncs automatically.
The sync queue counter in the bottom-left of the app shows how many check-ins are waiting to sync. A value of 0 Changes means your device is fully synced.