ASIN Definition
An Amazon Standard Identification Number (ASIN) is a 10-character alphanumeric identifier assigned by Amazon to every product listed in its catalog. It is Amazon's internal identifier, unique within the Amazon marketplace but not recognized or used outside of it.
How is an ASIN assigned?
When a product is listed on Amazon for the first time, Amazon either creates a new ASIN or matches the product to an existing one in its catalog, typically using the product's GTIN, UPC, or MPN as the matching key. If a match is found, the new seller is added to the existing listing rather than creating a duplicate. If no match exists, a new ASIN is generated.
Can two sellers share the same ASIN?
Yes, and this is by design. Amazon's catalog is structured around products, not sellers. Multiple sellers can list against the same ASIN, competing for the same product page. This is why product data quality matters: the content displayed on an ASIN's page is controlled by Amazon's algorithm and brand registry rules, not automatically by whoever created the listing.
Why does the ASIN matter outside Amazon?
For brands and retailers selling on Amazon, the ASIN is an essential reference in their product data. It needs to be tracked alongside internal SKUs and GTINs so that catalog updates, content submissions, and advertising campaigns can be tied to the correct listing. In a PIM system, ASIN is often stored as a channel-specific attribute, not a universal product identifier, but a necessary piece of data for anyone managing an Amazon presence as part of a broader multichannel strategy.
