MS Open Tech Open Sources WinJS, Part of the Windows App Platform

Today at Build 2014, Microsoft Open Technologies is open sourcing the Windows Library for JavaScript (WinJS) under the Apache 2.0 license on GitHub. This allows developers to use this powerful Windows development framework to build web apps across a variety of browsers and devices beyond Windows, such as Chrome, Firefox, Android and iOS.

A key role we play in the Microsoft Open Technologies Hub is taking top feedback we’ve heard from developers and using it to ensure Microsoft products and services are meeting their needs. Recently, we heard from developers who use HTML/CSS/JavaScript for their app development that they appreciate the reach it gives them across device platforms and they would like to see the same reach for WinJS as well.

WinJS embraces common open source development tools (like Grunt, LESS and QUnit), and is intended to be a collaborative process that allows developers’ contributions. You can check out and comment on a clear roadmap that’s been published on the GitHub site.

We are also happy to share that WinJS is also coming to Windows Phone 8.1 and Xbox One. That means that developers can deliver the same advanced, polished and modern user experience to a variety of browsers, including Chrome and Firefox, and to a variety of devices, including Windows, Windows Phone, Xbox One, iOS and Android.

WinJS powers many applications on the Windows Store like Skype, the Music app, Songza or the Seattle Sounders FC app (Go Sounders!). With WinJS developers can build polished web apps with media, animations and great interaction leveraging powerful features like Promises, Scheduler, data binding, and several well-designed, animated, touch-enabled user controls. They also have the option to combine WinJS with their favorite JavaScript libraries.

You can take WinJS code for a spin by visiting the “Try WinJS” site.


The engineering team working for MS Open Tech on WinJS has published additional information about the project on a blog post.

You should also check out the for more detailed information about the WinJS feature set, the WinJS Wiki page to learn about the roadmap, the “Try WinJS” site to play with the code and the GitHub page to get your hands on the code.

We can’t wait to see what you do with WinJS and look forward to hearing from you about how you plan to use it across Chrome, Firefox, IE, Windows, Windows Phone, iOS, Android…