Universal apps, also known as universal Windows apps, are apps that run on Windows, Windows Phone, and, in the future, on Xbox and perhaps other devices. Introduced at BUILD 2014 and made possible by the common APIs supported in Windows 8.1 and Windows Phone 8.1, universal apps represent the future of the Windows platform and enable developers to build one app that supports a range of devices, from desktops to tablets to phones. Join the fun as Jeff demonstrates how to build universal apps in XAML and C# and presents several sample apps that you can learn from.