If you don’t have the ability to add the tracking pixels or the Conversion Tracking Code to the “Thank You” page users land on after making a purchase, then you’ll need to use Postback URLs to track your sales.
A “Postback” is simply an automated notification that your affiliate network (such as ClickBank or MaxBounty) sends to ClickMagick whenever someone clicks your affiliate link and makes a purchase. This allows ClickMagick to record the sale, as well as any upsells, downsells and refunds, so it’s a more accurate way of tracking conversions if you’re willing to put in the work to set it up.
Take a look at some of these articles that go into more detail on specific parts of Postback URLs: