Q:

Getting the UPC in an MWS response

When using operation ListMatchingProducts or GetMatchingProductForId, is the UPC returned anywhere in the result?
If so, how do I access it?
If not, what service should I use to request it from Amazon? The Product Advertising API (formerly ECS)?

A:

Somehow I completely missed this in the Product Advertising API docs!
For the response group Medium and Large, access UPC in the resulting object using:
$ecsResponse->Items->Item->ItemAttributes->UPC

