To find the UPC/EAN/GTIN you can view the rss page of the product and search for the relevant tag such as <EAN>, or <UPC>. For example to get an RSS page for the 80GB Sony Playstation 3 which is listed on ASIN B001DTETLS, you’d use this URL:

http://webservices.amazon.co.uk/onca/xml?Service=AWSECommerceService&AWSAccessKeyId=youridhere&Operation=ItemLookup&IdType=ASIN&ItemId=B001DTETLS&ResponseGroup=Medium,Offers

You’ll need to substitue “youridhere” with your own AWSAccessKeyId. I’m not publishing mine here, but you can get one for free yourself by signing up to Amazon Web Services. You could also just Google for someone elses as other people do publish their keys.

You can substitue the domain extension in the URL if you want to look it up on other channels such as .com .de .fr .ca or .co.jp.

This RSS page has a bunch of useful information in it. The static URLs for images for example and also the lowest prices for both new and used and of course, the EAN and UPC code.

If you’re loading your products into Amazon using flat files (which you really ought to) then there’s another interesting option. Amazon’s flat files require the field “StandardProductID” (this is your UPC EAN or GTIN) and “ProductIDType” (this is just the right prefix for the “StandardProductID” you are using so the allowed values are UPC, EAN or GTIN).

What Amazon don’t tell us is that their is a fourth “StandardProductID” type the system will accept – have you guessed yet? Yes, we CAN put an ASIN number in “StandardProductID” and enter “ASIN” into “ProductIDType”.

This has a couple of advantages. Firstly, we don’t need to bother with an EAN, UPC of GTIN code and secondly we can be absolutely sure we’re listing onto the correct ASIN.

Some people may wish to NOT list onto the correct ASIN. Typically if you’re selling a product and you’re not the cheapest seller for it it is going to be very difficult to get the buy box on that product. So you stand a much better chance of a sale if your product sits on it’s own ASIN. To do this, you’d need to supply Amazon with a unique, and also incorrect UPC, EAN or GTIN code.