ASIN (Amazon Standard Identification Number)
The 10-character product identifier Amazon uses internally for every product. Found in product URLs as amazon.com/dp/B0XXXXXXXX. ASINs are supposed to be permanent but get reassigned more often than creators expect.
Every Amazon product has an ASIN — a 10-character alphanumeric ID — that uniquely identifies the listing. ASINs appear in product URLs as /dp/B0ABCD1234 or /gp/product/B0ABCD1234. Affiliate links typically include the ASIN plus your tag: amazon.com/dp/B0ABCD1234?tag=you-20.
ASINs are designed to be permanent identifiers, but in practice Amazon reassigns or deactivates them when products are discontinued, restructured, or removed. Your old affiliate link still resolves, but the page now shows a different product (or an empty listing). This is the most common reason Amazon affiliate links break — and Amazon does not notify creators when it happens.
Related terms
Affiliate link
A URL that contains a tracking parameter identifying you as the referrer, so the merchant can credit you a commission when the click converts to a sale.
GlossaryAffiliate tag
The unique identifier inside an affiliate URL that tells the network which publisher to credit. Different networks call it different names but the function is the same.