Building a payment gateway plugin

Page under construction. Steps I (Mike M) went through to teach a guy (Brad R) how to build a payment gateway plugin.

The four components of a payment gateway pie

1. Payment Options

Config form where user fills-in gateway account id and whatever other data is required by the gateway.

pgm-checkout.php

1. Add condition check to output hidden PAY_TYPE form/field if your gateway is set as the primary credit card processor in Payment Options
2. Add check for your gateway to condition that determines whether to show credit/debit card payment option to website visitor if one of the defined (checked for) credit card gateways is choosen in Payment Options.

pgm-payment_gateway.php

This is the script that passes the checkout order data to the gateway.