In the 2014 WWDC talk "Affiliate Tools for App Developers" there is a mention that the Lookup API can be used to lookup songs by ISRC code, but the Lookup API docs (https://www.apple.com/itunes/affiliates/resources/documentation/itunes-store-web-service-search-api.html)mention iTunes IDs, UPCs/ EANs, and All Music Guide (AMG) IDs, and not ISRCs.
Are ISRCs not available in Lookup in the end?
did you find this answer? i'm trying also to get the isrc codes of the songs already in itunes, but haven't found how. PLEASE HELP SOMEONE! :-/
Have you tried using the isrc parameter, like this: https://itunes.apple.com/lookup?isrc=12345678 I don't know if it works, but it's worth a try.
The API has been added: https://developer.apple.com/documentation/applemusicapi/get_multiple_catalog_songs_by_isrc
