What should happen when the internet drops mid-sale

In South Africa, the question isn't whether a store's connection will drop - it's how often, and at what moment. Load-shedding takes the router down, the backup data runs thin, and a till that only works online turns a full counter into a queue of customers waiting for a loading spinner.

The worse case is a connection that drops halfway through a sale. Was the customer charged? Was the stock taken off? Were their loyalty points spent? If the answer is some of the above, someone spends the evening untangling it.

Three things a till should guarantee

• Keep selling - a sale rung up with no signal is kept on the device and synced the moment the connection is back
• All or nothing - the order, its products, the stock, gift card, promo code and points are saved together, or not at all, so there's never a half-finished sale
• Pressing pay twice is safe - if the connection drops just as a sale goes through and someone presses again, it's recognised as the same sale instead of charging twice

Making sure offline sales come home

Offline sales are only safe if they actually sync. In Budstack, a green or red dot shows whether the till is connected, the end-of-day checklist names any sales still waiting on the device, and cash-up waits until they have arrived - so the drawer is reconciled against every sale, not just the ones that made it through.

Updates that don't interrupt anything

The same thinking applies to updates. A new version of the app arrives on every device by itself, but only switches over when no sale is in progress and nobody is typing - so a busy Saturday never stops for a refresh. If a single screen does run into a problem, it shows a clear message with a way to try again, and the rest of the app keeps working.

None of this is glamorous, but it's the difference between a system built for a real South African counter and one built for a demo on fast office Wi-Fi.