When your FBA shipment arrives at an Amazon FC, it goes through a receiving dock where cartons are scanned, weighed, and checked against your shipment plan. This is why carton count accuracy matters — discrepancies here trigger a reconciliation process.
After receiving, units are individually scanned and placed into Amazon's inventory system. Items are then stored in Amazon's stow locations — which are random by design. This randomization improves picking efficiency across the FC.
When a customer orders, Amazon's system identifies the nearest FC with available inventory and generates a pick path. An associate picks the item, it is packed and labeled at the pack station, and sent to the carrier sortation area.
Understanding this process explains why correct prep matters: a mislabeled unit that scans as the wrong ASIN at receiving creates an inventory error that results in the wrong item being shipped to a customer — a return and a metrics hit.