I am trying to port a legacy spaghetti-code commerce system using PayPal to Drupal 8, Commerce2, and Commerce PayPal. I can make neither head nor tail out of either PayPal’s documentation nor Commerce PayPal’s documentation to even tell which API I’m using. Maybe somebody can direct me appropriately:
The existing system, I think, is using PayPal Express Checkout, but I'm getting the impression that might be deprecated. There’s a “Buy Now” button that POSTs a form to PayPal (cgi-bin/webscr) including an email address for a “business” account owner, pricing information, a “return” URL, and “notify_url”.
All the options I currently see involve creating a sandbox account and popping credentials from that into the newer system. I can't for the life of me understand what purpose those credentials serve. Are they to test payments coming into my sandbox account? Does this mean that prior to going live, I have to my client create a set of credentials so that payments can be received by her business account? In the end, the system I'm building needs to duplicate the functionality of the old, wherein there are any number of merchants with their own business accounts. Does this mean that each of them will have to create a set of API credentials and forward them to me for inclusion into the system?
