Hi all,
We are designing the edge-to-cloud sync pipeline for an enterprise visitor management system designed to run on dedicated self-service reception kiosks and tablet terminals.
The Problem
During network flaps or ISP degradation at facility entrances, the check-in kiosks must operate completely offline:
Accept check-in data, capture visitor photos, and issue temporary visitor badges locally.
Queue badge issuance events and cryptographic visitor tokens locally (in an encrypted SQLite/IndexedDB store).
Re-sync bidirectionally with the central PostgreSQL backend via WebSocket/gRPC once connectivity is restored.
Here is a simplified illustration of our current local worker queue:
typescript interface QueuedVisitorCheckIn { localId: string; visitorUid: string; signedBadgeToken: string; // HMAC-SHA256 signed at edge checkInTimestamp: number; syncState: 'PENDING' | 'SYNCING' | 'COMMITTED'; retryCount: number; } async function flushOfflineCheckInQueue(queue: QueuedVisitorCheckIn[]): Promise<void> { for (const record of queue) { try { await apiClient.post('/api/v1/visitors/sync-batch', record); record.syncState = 'COMMITTED'; } catch (err) { if (err.statusCode === 409) { // Handling clock-skew / concurrent check-out edge case handleConflictResolution(record); } break; } } } Where We Need Community Input 1. Conflict Resolution Strategy: If a visitor pre-registers online while an edge kiosk creates an on-the-spot walk-in record with the same phone/email during an offline partition, what CRDT or reconciliation pattern have you found most robust? 2. Offline Photo Buffering: What is the most resilient approach for handling temporary image buffers before cloud bucket sync without exhausting client disk limits on lightweight kiosk hardware? Would love to hear how other teams handle offline queueing and eventual consistency for high-throughput front-desk check-in terminals! 
