Offline Queue & Synchronization Engine

Vritti Lens is engineered to function continuously during internet connectivity drops or power disruptions.

Architecture

When an employee scans their face at a Vritti Lens kiosk:

Local Vector Comparison: Face embeddings are processed locally on-device without calling an external API.
Local SQLite Event Queue: Successful identifications generate an AttendanceEvent record assigned a unique UUIDv4 key, stored in the tablet’s local SQLite database.
Audio-Visual Feedback: The kiosk plays a confirmation audio tone (“Attendance Marked for [Staff Name]”) immediately.

Automatic Sync Behavior

Vritti Lens runs a background sync worker that monitors network status.
Once Wi-Fi or cellular connectivity is restored, the queue sync worker flushes pending events in batch payloads (up to 50 events per batch) to the backend API.
Idempotency Guarantee: Because every scan event carries a unique client UUID key, network retries or duplicate uploads are deduplicated safely by the server without double-counting.

Monitoring Sync Status

On the top header of the Vritti Lens scanning screen:

Green Cloud Icon: Fully synchronized. All events pushed to server.
Orange Cloud Icon + Number (e.g. 14): Offline mode. Number indicates pending events stored in local queue.
Red Warning Icon: Sync error or invalid credentials. Tap to open diagnostic PIN screen.