background custom domain forwarded information integration item passed posted price purchase reaches show string thank-you-page total txn url user

I am using the custom thank you page that is being forwarded back to my domain. I would also like to pass the item purchase name and total price, but they do not show in the URL string.

No, if you need that information, please see our integration section. That information will be posted to a URL you specify in the background and when the user reaches your thank you page, you can look up that information using the txn_id being passed to the thank you page.