I'm currently building a program to generate test data with PayPal. I need to generate purchases using express checkout. I'm able to automate the creation of a purchase with set express checkout, but I was wondering if there was some API call to have a buyer purchase that specific purchase. For example, is there a way to automate going into https://www.sandbox.paypal.com/cgi-bin/webscr?cmd=_express-checkout&token= and confirming that purchase? Thanks.
EDIT: For more clarification, I'm talking about automating step 3 in this link https://developer.paypal.com/docs/integration/web/web-checkout/