API - Get my listing with item's code/key

Hello Everyone, :wave:

I’m using GameFlip’s API to delete and re-upload my listings.
But i want to improve my script, I want to check what item has been sold, retrieve the “key/code” to update my stock. That way when I re-list, I will re-list without the sold items.

My problem is when i get my listing throught GET request, I get a lot of property about my items but without the key/code :slightly_frowning_face:

Is it possible to do that? Or is it not possible for security reasons? :lock:

Thank you all ! :v: