As I currently understand, Cost of Goods Sold (unit cost) is available for retailers who pay for Square for Retail (with Inventory Plus features). Is this data accessible in the API? if so, is it returned from the catalog endpoint?
Unfortunately, it is not returned in any APIs. Square for Retail (same as Square for Restaurants) do not have any API related features/fields.
Are there any plans to add the Square for Retail fields to the api?