How to integrate coupons with your payment processor or e-shop
If you want to recognize which affiliate referred the sale according to the coupon code which was used during the purchase, then this is a theoretical overview of how it should be integrated.
In order to make this work, you have to use the same coupons in your payment processor (or e-shop) as in your Post Affiliate Pro. Basically, you should generate coupons in Post Affiliate Pro (https://support.qualityunit.com/542971-Generate-coupons) and then import these coupons into your payment processor ...