I have an e-commerce SaaS offering where merchants can come and open their online stores automatically, pretty similar to Shopify. When buyers make transactions on my clients (merchants) stores, how can I charge merchant a certain percent and transfer it to my account? I went through Adaptive Payment APIs and it seems like it is doable. However, I'm using Express Checkout for buyers to pay merchants. On the other hand, there is parallel payment in Express Checkout but it shows the buyer in the transaction details that he is gonna pay me in addition to the merchant. I want this to be transparent to the buyers where they see that they are paying to the merchant only, and in the background I get a parecent. I don't know how Shopify is able to use Express Checkout and charge a markup on every transaction happens on their merchant sites.
Thanks