It's necessary to include also bundle ID in your payload if you use store kit API to get transactions (https://api.storekit.itunes.apple.com/inApps/v1/transactions/${transactionId}). For example: jwt_payload = { "iss": MY_ISSUER_NUMBER, "iat": time_now, "exp": time_10_min, "aud": "appstoreconnect-v1", "bid": "com.example.app" } Hope this helps someone!