We are about to migrate current HPSDK Payment Gateway implementations to Shopify Payment Apps. We use checkout webhooks (create/update) for the additional information.
The problem is that on the page https://shopify.dev/apps/payments#prohibited-actions all other but Payment APIs are strictly prohibited. Also the gateway payment request included the x_reference information but this is missing in the new payment request https://shopify.dev/apps/payments/processing-a-payment#request-body-example
Is there a way to access the checkout id or order reference for payment processing? Because lack of this essential information, could we use webhooks to supplement the Payment API information?
Did you get a way to resolve this issue? Or did you get any reply from Shopify?
We have the same problem as part of the migration that we are doing from HPSDK to the new platform. We were also using the checkout webhooks, now prohibited.
It appears that Shopify does not allow us to complete the order with all the missing information.
Anyway, we have contacted support regarding this issue and we are still waiting for a response from them.
We contacted Shopify support, but it was useless. They don't know how to do it and keep insisting on asking here in the forums.
According to the documentation is not possible, and support is not willing at all to provide any method, information, or way of how to do this.