inventory-tracking

Shopify's checkout natively holds inventory during the checkout flow to prevent double-purchasing the last unit. For very high-concurrency launches, set purchase limits using Shopify Scripts (Plus) or use a waitlist app to control demand.

Use optimistic concurrency control: read the inventory level with its version, then run a conditional UPDATE filtered on that version so concurrent writes fail and retry. Retry up to 3 times with increasing delays, and log every reservation to an audit table.

WooCommerce has native stock management with three backorder modes per product: do not allow, allow with customer notification, or allow silently. Its Hold stock setting reserves inventory during checkout for a configurable window, defaulting to 60 minutes.

Stock management must be enabled both globally in WooCommerce settings and on the individual product's Inventory tab. If either is off, orders will not decrement stock quantities.

Run a background job every 5-10 minutes that finds active carts whose updatedAt timestamp exceeds a 30-minute TTL and releases their reservations. Make the release idempotent by checking the transaction log for an existing release record before decrementing.

Platform-native tracking is almost always the right starting point. Build custom logic only for requirements platforms cannot meet, such as complex multi-warehouse routing, custom reservation windows, or external WMS integration.