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.
For more clarification, I'm talking about automating step 3 in this link
I use nopCommerce as my selling platform. They have a prebuilt PayPal Express module. Have you considered using a pre-built e-commerce solution?
In PayPal, it looks like there is no API to finish such website operation, but you can try some testing tools to do this part repeatedly, such as QuickTest Professional.
How about selenium to do the work for you. That's how we test our SDK integration too. Use any testing framework supporting selenium and you should be fine.