Hi everyone...I was hoping for some guidance before I jump in to integrating PayPal into my e-commerce web app since there are several checkout flow options available. I have already integrated a credit card payment flow with connections to several merchant processors, but now I'd like to offer PayPal as an option as well. I have two pre-requisites and hopefully there's a PayPal integration option that matches both:
1) Multi-user integration
My e-commerce web app is currently used by many accounts across different domains/subdomains so I'll need an integration option that allows for users to connect their PayPal account as easily as possible to their checkout flow, hopefully something as simple as adding their PayPal username to the cart options in the back-end like they currently do with our other payment processing options.
2) Keep customers on the site
During the checkout flow, the current payment options always keep the customer on the same site when paying by credit card and I need a PayPal integration option which does that as well. I was looking at PayPal Checkout and it seems to work well in that regard, but I don't know how well it fits with my first pre-requisite of multi-user integration...it seems to work only under a single PayPal Client ID. Maybe this Client ID be swapped on the fly?