Why your point of sale should work when the internet does not
A till that stops taking money when the line drops is not a till. What offline-first actually means at a counter, and what it costs to build.
Every retailer in Sri Lanka has had the afternoon where the connection goes and the queue does not. What happens next tells you what your point-of-sale software is really worth.
Most cloud billing systems simply stop. The screen shows a spinner, the operator starts writing on a pad, and the day-end reconciliation becomes an evening of typing. The sales are not lost, but the accuracy is — and so is the customer who left.
Offline-first means something specific: the till writes to local storage first and synchronises afterwards, rather than the other way round. The sale is complete the moment the drawer opens. When the line returns, the queued writes replay in order, and anything that conflicts is surfaced for a human rather than silently resolved.
It is more work to build. The queue has to survive the browser being closed, the replay has to be idempotent so a double-send does not double-charge, and stock has to reconcile against what the server believes rather than what the till assumed. But it is the difference between software that helps on a good day and software that holds up on a bad one.