Your internal product identifier. Maps to an ASIN on Amazon. Used for inventory tracking across systems.
ExampleYour internal SKU 'BLK-MED-100' might map to ASIN 'B0XXXXXX12' for the black medium-size version sold on Amazon.
SKU is the warehouse and ERP identifier; ASIN is the Amazon identifier. They map one-to-one in most setups. SKU-level reporting is what your operations team uses; ASIN-level is what Amazon Ads shows.
Mapping discipline matters when reconciling Amazon reporting with your own P&L. SKU-to-ASIN mismatches are a common source of attribution drift.