Apple has released an Apple Watch developer kit called WatchKit to let firms start building apps ahead of its release next year.
The iOS 8.2 beta SDK will allow developers to start creating apps specifically for the Watch interface. Instagram, ESPN and American Airlines have already promised to build apps.
Developers can build versions of apps with WatchKit so they can be used on the Apple Watch, but it will require a connection to an iPhone.
"When your app is launched on Apple Watch, the WatchKit extension on iPhone runs in the background to update the user interface and respond to user interactions," Apple's WatchKit website notes.
Developers can also access features in the toolkit that open functions such as ‘glances’ so that apps can display 'read only' information on the watch face, and 'notifications' that can offer interactivity.
However, at present developers will not be able to build native apps for Apple Watch, as this functionality is slated for full release "later next year".
Philip Schiller, Apple’s senior vice president of worldwide marketing, said that the launch of WatchKit is a key stage in the progress of Apple Watch to market.
“Apple Watch is our most personal device ever, and WatchKit provides the incredible iOS developer community with the tools they need to create exciting new experiences right on your wrist,” he said.
Instagram CEO Kevin Systrom was also upbeat on the release, claiming that it will offer many new features to fans of the photo service.
“Apple Watch allows us to make the Instagram experience even more intimate and 'in the moment',” he said.
“With actionable notifications you can see and instantly 'Like' a photo or react with an emoji.
"The Instagram news and watch list allows you to see your friends’ latest photos, follow new accounts and get a real-time view of your Likes and comments.”
At present it is not clear when Apple Watch will come to market. A leaked transcript by a top Apple executive suggested it could be as late as June 2015, although March seems the most likely.
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