Amazon already allocates its ASIN number to products. Why do I also need a GS1 GTIN?

ASIN stands for Amazon Standard Identification Number, and it is a product identifier assigned by Amazon for use internally at Amazon facilities.

To create an ASIN on Amazon, you must first fill in the mandatory attributes, including your product’s GS1 GTIN.

Amazon relies on GS1 GTINs to manage its global catalogues. Both numbers are required to sell on Amazon.