Stock holds that survive a flash sale
Reservation windows, soft locks, and why pulling inventory every thirty seconds still oversells limited SKUs.
Polling warehouse stock every half minute feels responsive until checkout spikes. Between polls, two customers can both see three units of a limited edition and both complete payment. The warehouse discovers the conflict when pickers reach an empty bin.
A short reservation hold at add-to-cart or at payment authorization buys time. Fifteen minutes is common for apparel; perishable goods often need shorter holds plus a release job that returns unused reservations without waiting for cart abandonment events.
We prefer push updates from the warehouse for high-velocity SKUs and keep polling as a safety net for quieter catalog sections. The integration map should name which SKUs use which path so on-call engineers know where to look first.
If your marketplace channels also sell the same stock, holds must be shared. Otherwise the storefront looks careful while the marketplace quietly oversells the same carton.