Do I need to add ASINs to products?

Adding ASINs is optional, as it is only one of the multiple ways to identify the product. When ASIN is not specified, Salestio will prioritize the barcode specified on the product page in the Barcode field on the Shopify product page (UPC or EAN).

ASIN can be necessary when you don't know the barcode of the item or it doesn't exist. Attempting to send such an item to Amazon will result in the following log error:

externally_assigned_product_identifier: 'External Product ID' is required but not supplied

If you want to use an ASIN instead, click “Add ASIN” in the Selling List. To find an ASIN of the item, look up its page on Amazon and check the description.