Field notes
The storefront offered a size the warehouse had already packed out
Available-to-sell was a nightly file. Reservations were real-time. Between the two, a popular size stayed on the product page until the next morning.
The 3PL sent a stock file at 02:00. The storefront reserved units at checkout. Overnight sell-through on one size emptied the bin. The product page still showed ‘in stock’ and a two-day delivery promise until the next file landed.
Buyers paid. The pick list came back short. Customer service issued delays and a handful of cancellations. The application had done what it was told: trust the file, not the reservation log.
Inventory reviews are unglamorous. They are also where money and reputation meet. We reconstruct a handful of oversells from the order, the reservation, and the warehouse movement — in that order — and date the first night the file and the live stock diverged.
If you list on a marketplace as well as your own shop, run the same reconstruction twice. Marketplace clocks and your own clocks rarely fail on the same hour.