GearChase lists products from more than 950 stores. Almost all of them work with us through two affiliate networks, AvantLink and Impact. Each store publishes a product feed: a file with its products, prices, stock status, images and links. We import those feeds. Some stores run on Shopify, and for those we read the product list the store itself publishes. Amazon appears only occasionally, in deals picked by hand and linked through the Amazon Associates program.
We store the values exactly as each store sent them. When we tidy something up, like a product's category or which sizes belong together, we keep that in separate fields, so the store's own data is never overwritten.
We list only stores we have an active partnership with. When a store leaves its affiliate program, its products come off GearChase.