I run an invoicing/accounting platform. I'd like to integrate PayPal so that my users' customers can pay my users with PayPal. Nothing fancy, I am happy to have it just be a button and for the customer to go to PayPal to actually make payment (which I believe is PayPal Payments Standard).
In my case, though, I would like to charge my users a small fee when they get paid by their customer (like an app_fee that goes to our platform's PayPal account). Is this possible with PayPal Payments Standard? And if not, which API would I need to use?
