If I’m understanding you correctly you want a process where the customer is redirected to the accept hosted form, enters payment, and when they hit continue on the receipt page the transaction Id is included in the response.
I use the transaction Id in my process as well, and I’ve found that Webhooks are by far a better option. For instance, my app uses the transaction id to clear shopping carts. This can also be done when the customer hits continue, as the cart is tied to a cookie that can be killed. I have that built in too. If I had to pick one or the other I would pick Webhooks hands down. What do you do if a customer does an X out instead of hitting continue? In my case the cart isn’t cleared and the order has no transaction tied to it to indicate successful payment.
The Webhooks come very fast. If the customer prints the receipt before hitting continue, 95% of the time the Webhooks will beat them to your server. I was sending a series of test orders today and finally had 2 that took 3 minutes to arrive. The rest hit in a few seconds.
I think at this point you may have only been considering doing the calls that are on the doc page, all of the http requests. What you want to do is setup an endpoint and enroll in events. If you’re doing an authonly then you enroll in authonly notifications. The transaction id will be delivered in the payload that hits your endpoint. Then you can do whatever it is you need to do with it just the same as you would if it came in the receipt page redirect.