Apple launches WatchKit SDK so developers can start building apps for Apple Watch

Apple’s long-awaited developer kit for its smartwatch is finally here.

Today’s release includes a WatchKit extension for the iPhone, and user interface resources and tools for the Apple Watch itself. The WatchKit is included in the Xcode 6.2 with iOS 8.2 software development kit in beta that developers can now download.

Since the watch isn’t entirely independent, the extension is what runs in the background on the iPhone when a watch app launches. It updates the interface and responds to user interactions with the app on the watch.

The WatchKit enables developers to build for the Apple Watch in three different ways: Watch apps, “glances,” and actionable notifications. Watch apps are apps that users can interact with directly from the watch and have a full user interface. Glances provide users with quick information nuggets or updates about an app on their iPhone, and notifications show up on the watch to alert users and enable them to take action from the watch.

Also note that the site says that, “Starting early 2015, you will be able to deliver innovative new experiences to your customers on their wrist,” a vague hint about the watch’s release date. While “early 2015” could mean almost anything, we’d venture to say that it’ll be sometime in the first half of 2015, if not in the first quarter.