Developers can now start creating apps for the Apple Watch. Apple is today releasing WatchKit, a toolkit that allows developers to begin coding and testing apps for its upcoming smartwatch. "WatchKit provides the incredible iOS developer community with the tools they need to create exciting new experiences right on your wrist," Apple Marketing Chief Phil Schiller says in a statement.

Native watch apps won't arrive until later next year

Apps can connect with the Apple Watch in three different ways. The first is a standard Watch App, which has its own interface and features. The second is by adding a page to the watch's Glances screen, which contains short snippets of information, like news or sports scores, that wearers can swipe through. The final thing that apps can do is create actionable notifications, which can be used to simply let someone read and respond to a message or can be programmed to allow more complicated actions — a smart home, for instance, could allow someone to turn their house lights off from their wrist once they leave home.

Watch apps will be capable of a lot of the helpful features that Apple has been adding into iOS apps, too. That includes the ability to use Handoff so that wearers can pick up an app on their iPhone where they left off on their watch. Apps will also have the ability to use AirPlay to stream media.

For now, Apple isn't allowing developers to create native Watch apps — that is, apps that run and exist entirely on the Apple Watch. That feature will come later next year, making it sound as though it won't be available when the watch first launches. Instead, the apps that developers are able to start building today will all be extensions of iPhone apps, meaning you won't be able to use them without your phone nearby. That'll probably help the watch's battery life because the apps will largely be running off of the phone, but it'll likely limiting too, giving developers fewer opportunities to create interesting new experiences.

The watch comes in two different resolutions

Even though the two Apple Watch models have only slight size differences, it turns out they have different display resolutions. The smaller model, which has a display height of 1.5 inches, has a resolution of 272 x 340 pixels. The larger model, which has a display height of 1.65 inches, has a resolution of 312 x 390 pixels. Apple's documentation makes it seem like that won't make a huge difference for developers, since information generally just flows down the Apple Watch's screen, but it's still two different resolutions that they'll have to accommodate right out of the gate.

Apple has already been working with a number of developers to create Watch apps, including ESPN, American Airlines, and Instagram. Instagram's Apple Watch app will allow people to like or respond to photos right from a notification, browse through their photo feed, and even follow new accounts. "Apple Watch allows us to make the Instagram experience even more intimate and in the moment," Instagram CEO Kevin Systrom says in a statement. ESPN's app will deliver sports scores and news through Glances, and American Airlines' app will update wearers on gate changes and other flight information.

Apple isn't providing an update yet on when it'll actually release its smartwatch. It's still stating that it'll come in "early 2015," though leaked remarks from one Apple executive suggest that it might be sometime next spring.