Issue
Currently I have multiple subscription offers available for yearly/monthly subscriptions. Each of the subscription offers have multiple different custom codes available. When the customer buys a subscription and the receipt is being handled in the backend, I need to know which of the custom codes was used.
What I have tried
When i call the https://buy.itunes.apple.com/verifyReceipt I get the values offer_code_ref_name and promotional_offer_id. The offer_code_ref_name is the subscription offer name AND NOT the custom code.
I tried to get more info using the https://api.storekit.itunes.apple.com/inApps/v1/subscriptions/{transactionId} request, but it does not give me any info about the custom code used either.
I do however see which custom code has been used if I go to Sales and Trends > Sales and Trends Reports and download Subscritpion Reports. There the offer code can be found ref. as "Promotional Offer ID"
my question
How can I get which custom code was used when purchasing a renewable subscription using transaction id or transaction Receipt?
