This chapter described most of the classes you have to work with to process Apple Pay payments. It also described the protocol used by the payment sheet to communicate user actions to its delegate so that you can respond appropriately. Finally, the chapter listed a few additional classes that you must work with to access address components, such as a person's name, phone number, and postal address.
This is the end of Apple Pay Essentials, conceived to help you add Apple Pay support to your apps. This book introduced the world of online payments, describing how payment associations, payment gateways, and banks work together to transfer funds from a customer's payment card to a merchant's account. Apple Pay improves on this model by adding convenience, privacy, and security to the process.
You learned about using the REST API in your client app to communicate with server web apps that provide the information that the app needs (such as details about the products you have for sale and...