What is an ASIN?

Amazon's own ID for every product in its catalog.

ASIN stands for Amazon Standard Identification Number - a ten-character code (like B0BXXXXXXX) that Amazon assigns to every product in its catalog. It is Amazon's internal ID: one listing, one ASIN, shared by every seller offering that exact product.

For an arbitrage seller the ASIN is the unit of everything: you match a retail product to an ASIN, you check the ASIN's price history and sales rank, you decide whether you are allowed to sell that ASIN, and you compete for its Buy Box. Sourcing tools work by matching retail products to ASINs - primarily by barcode, with title matching as a fallback - and pricing the difference.