Express Checkout is PayPal’s premier checkout solution. It allows a customer to check out on your site, log into a PayPal account, and purchase your goods or services. Express Checkout puts PayPal in charge of data security with regard to the customer’s billing and credit card information and removes that non-trivial PCI compliance burden and liability from you as the merchant, allowing you to focus on the aspects of your application that differentiate you in the marketplace. In this chapter, we will look at what distinguishes Express Checkout from other generic workflows and take an in-depth look at its integration points. Then, we’ll put theory into practice by building a non-trivial (and hopefully, fun) GAE project that hacks on Twitter data and implements Express Checkout for payment processing.
PayPal’s official documentation for Express Checkout is available online.
Let’s start by looking at the process flow of a typical checkout and juxtapose it with an Express Checkout to better understand the underlying value proposition.
Figure 2-1 shows the typical checkout flow a user experiences when buying goods or services online. It includes the following steps:
Customer clicks the checkout button on your shopping cart page.
Customer enters all shipping information.
Customer chooses her payment method and provides all the relevant billing and payment information.