When a supermarket in Kisumu loses internet, the till doesn't get to stop. StockPoint POS was designed around that reality from day one.
Every till is a local source of truth. Sales, returns, stock adjustments and cash drops are written to a local SQLite store and an outbound queue. A background worker drains the queue whenever connectivity returns, using deterministic IDs so retries are safe.
The hard part isn't the queue — it's the conflict resolution when two tills sell the last unit. We walk through the CRDT-ish approach we use, plus the operational guardrails (per-SKU reservations, end-of-day blind counts) that keep stock accurate.