SKU

A SKU (Stock Keeping Unit) is a unique alphanumeric identifier assigned to a specific product variant in a retailer's catalog. Each distinct combination of product, size, color, and other attributes gets its own SKU, allowing inventory systems to track stock levels and sales at the variant level.

In retail data APIs, SKUs are used to precisely identify the exact product you want details for. A product search might return a general product card, but the product detail endpoint typically requires a SKU to return variant-specific pricing and stock status.

SKUs are retailer-specific - the same physical product will have different SKUs at Target vs. Walmart vs. Best Buy. Cross-retailer product matching requires mapping products across different SKU systems, typically using common identifiers like UPCs or EANs.