I have been tasked to write a new payment type of mod for a client. Since it needs to use curl, I based my first try on the authorize.net module. I knew that it was was more complicated than I needed but figured it would be easier to delete stuff than add it. Well, getting frustrated.

This module is actually a credit application module where the processor approves or disapproves the credit app but also redirects to the website to finish the application as they take the payment, not the site owner.

So in some ways it's pretty simple. Send the basic information to the other website and receive a response. So really maybe a combination of code from authorize.net and paypal express?

What's the best way, i.e., easiest, less problematic, to do this?