Retail connectivity fails at the worst moment—Saturday rush, monsoon weather, or an ISP blip. POS software should degrade gracefully and keep selling, not freeze the queue while someone reboots a router.
Patterns that hold up in stores
- Persist carts locally with durable IDs and crash recovery
- Retry sync with backoff and surface a clear “pending upload” state
- Define who wins on price overrides, returns, and duplicate receipts
- Keep tax and receipt rendering available without the cloud
Test the network you wish you did not have
Simulate latency and packet loss. Pretty demos on gigabit Wi-Fi lie. Offline-first POS is equal parts engineering and training—staff need to know what “pending” means and when it is safe to close the till.
