Great question — answering as the UphillTech team:
You can check generated links on the US site and the UK site with their link checker tool. This will tell you if you get credit for purchases. It won't tell you if you get API credits. The Product API is documented here - you should use the "DetailPageURL" response attribute for the URL. You can build your own links like this, subbing in the correct values: "http://www.amazon.co.uk/exec/obidos/ASIN/#{asin}/ref=nosim/#{uk_associate_id}" Note - that URL is for the UK site. If you generate your own links, they won't count towards your API usage credit. See here for more details. Hope that helps.
Full answer by dkam: https://stackoverflow.stackexchange.com/a/5853576 (CC BY-SA 4.0).
Need it done for your business? UphillTech.
