In this chapter, you explored the amazing world of notifications. Even though notifications are simple in nature and short-lived, they are a vital part of the iOS ecosystem, and users rely on them to provide timely, interesting, and relevant updates about subjects that matter to them, right there and then. You saw how to go from the basics, simply scheduling a notification, to more advanced subjects, such as custom actions and implementing grouped notifications. You saw that service extensions allow you to implement great features, such as true end-to-end encryption, or enrich push notifications with content that is stored on the device.

You then implemented a content extension, and saw how a content extension can take a simple, plain notification, and make it interesting, rich, and more relevant. The example of a calendar that appears with event invites comes to mind immediately, but the possibilities are endless. Proper usage of notification extensions will truly make your app stand out in a positive and engaging way.

The next chapter focuses on another extension: the Today extension!