Selling Online When Your Stock Lives at the Counter

Retailers with physical outlets usually have a billing system that predates any thought of selling online. The storefront is the easy half of that project.

Pick one source of truth

Web and counter cannot both own inventory. In practice the billing system should stay authoritative, because that is where staff already work, and the website should read from it. The alternative — asking staff to update two systems — fails within a week.

Reserve at checkout, not at dispatch

If web stock only decrements when an order is packed, two customers can buy the last unit. Reserve on payment, release on cancellation, and make the reservation window short enough that abandoned carts do not lock inventory.

Expect the API not to exist

Plenty of Indian billing packages have no integration surface at all. That is workable: read the database directly on a short interval, or export on a schedule. What matters is that the sync is observable — someone should be able to see when it last ran and what it changed.

Build the reconciliation report on day one

A daily report listing every product where web and counter disagree turns a class of invisible failure into a five-minute morning check. It is the single highest-value thing you can add to a POS-integrated store.