Point of Sale

On patchy mobile data the reply gets lost more often than the request, so the phone sends again. How a key on every sale, payment and stock movement makes a retry return the first answer instead of recording a second sale, across 172 actions on the app and API.

Till losses happen at the refund, the price change and the drawer opened for change. Refunds and price changes can now need a supervisor’s PIN, every no-sale opening is logged, and each Monday the cashiers who stand out from their colleagues are named.

An internal auditor asks for one cashier’s shift: every void, refund, over-limit discount, price change, no-sale opening and reprint, with who authorised each, and the drawer signed by someone else. What the till holds for each line, where to pull it, how often to look, and which lines we can add.

A closed till waits for a supervisor who is not the cashier, the variance is journalled to Cash Over and Short when they sign, every M-Pesa and card payment keeps its reference, and each sale keeps the cost it was made at.

A fitting, a cut, a service, a callout. A service sells at the counter with no stock, no shelf check and no cost of goods, and a refund never puts labour back on a shelf.

A rule about receipts can be an integration, an architecture or an accreditation, and only the first is something you can shortlist for. The third is answered by a public register in about two minutes and almost nobody evaluating from outside the country knows to look. And our own position against one European regime, shape by shape.

Four East African authorities run four separate schemes against four separate interfaces, and one question separates them: can the sale complete when the authority cannot be reached? We built for one answer, for one country: the sale completes and files afterwards, so the receipt your customer carries out of the shop is printed before the fiscal reference exists — and a POS filing that fails is retried every hour rather than stranded.

Victoria makes a second-hand dealer keep goods exactly as they arrived for seven days, record where each item is stored, and — for scrap metal — never pay in cash. Our till is built for the other direction entirely.

Japan's misleading-representation penalty is three per cent of the sales you made of those goods during the period the claim was displayed. We can produce the sales for any window, and a dated price list shows when a list price was in force; nothing here records when a claim was.

Hold a cheque too long and the drawer can be discharged to the extent of the damage your delay caused. A cheque carries three dates and a payment row here has one column — and the till cannot take one at all.

Canada's legal-tender limits are written in denominations, and a till records a payment as one number. The gap is not a compliance problem — it is a modelling one, and two of the missing pieces are worth having anyway.

British price marking treats a price as five properties: a number to a stated precision, a unit, a condition, a currency and a relative type size. A price field is one of them — and two of the five belong to how something is printed.