PayPal Express Checkout is easy to add to an existing ordering system. See how in this episode

In this episode I show how to add Active Merchant's functionality to a Rails application to make a fully-functional checkout process.

Active Merchant is a great library for handling credit card transactions. In this episode I will show you the basics of using it to communicate with PayPal's gateway.

This episode shows how to encrypt the variables passed to PayPal and verify the authenticity of the payment notifications (IPN).

PayPal's IPN (Instant Payment Notification) service allows your app to get confirmation when an order is processed. In this episode I use IPN to mark a cart as purchased