An ASIN (Amazon Standard Identification Number) is a unique product identifier assigned by Amazon. Every product in the Amazon catalog has an ASIN. For books, the ASIN is the ISBN. For all other products, Amazon assigns a proprietary identifier.
Multiple sellers can list against the same ASIN, which creates the competitive marketplace dynamic that makes repricing necessary. When mapping your catalog in PriceLeap, each internal SKU is matched to its corresponding ASIN to enable competitor monitoring and Buy Box tracking.