Chapter 2
WatchKit Extension Overview

Now that you’ve learned about the watch and what it can do, how do you actually get your app on it? You want your app’s icon on your users’ Apple Watches, and to do that you need a WatchKit extension. Why an extension and not just an app? Apple Watch apps (for now) need to exist as a part of their companion iPhone app primarily for distribution—when users install the iPhone app on their phones, they’ll be able to install the watch app on their watches. This will add an app icon to their home screen, and from there they can move the icon around, launch the app at will, and show it off to their friends. By bundling the watch app and iPhone app, Apple circumvents the problem of having an App Store on the watch by using the App Store on the phone. So, since you know you’ll need to create a WatchKit extension, let’s get started!