A point-of-sale system that takes its catalogue from Pantheon and posts its sales back into it, while needing no Pantheon licence on any of the tills.
A retailer running Pantheon already has the hard part solved: the items, the price lists, the discounts and the stock all live in one place, and the books get closed there. What that retailer does not have is a cheap way to put another till on the shop floor. Traditionally the terminal is another seat, so the cost of opening a lane — or a pop-up, or a second shop — is a licence as much as it is a piece of hardware.
This is a point-of-sale application in its own right, with its own local store, that treats Pantheon as the system of record rather than as the thing it runs inside. It pulls items, prices, discounts and stock down, and posts sales, returns and cash-up back through a single integration service. One channel to the ERP, however many terminals stand in front of it — which means the twentieth till costs a tablet, not a seat.
The hard parts are the ones a shop notices. It has to keep selling when the network drops, which makes it offline-first by necessity: queue the documents, reconcile on reconnect, and never let the same sale land twice. Fiscal receipts follow rules somebody else wrote and cannot be negotiated with. A return has to arrive in the ERP as the document type the accountant expects, not as a negative sale. And end-of-day has to agree with the drawer, because a POS that is approximately right about money is not a POS.