Universal Windows Platform apps

Universal Windows Platform (UWP) apps (formerly Windows Store apps and Metro-style apps) are apps that can be used across all compatible Microsoft Windows devices, including personal computers (PCs), tablets, smartphones, Xbox One, Microsoft HoloLens, and Internet of Things. UWP apps are primarily purchased and downloaded via the Windows Store.

Starting with Windows 10, a UWP app is called a "Windows app"; a UWP that meets Microsoft's specifications, installed from Windows Store, is a "Trusted Windows Store app"; and other application programs running on a desktop computer are "desktop apps".

Windows apps first became available under the name "Metro-style apps" when the Windows Store launched in 2012 and were marketed with Windows 8.

In Windows 8.x, Metro-style apps do not run in a window. Instead, they either occupy the entire screen or are snapped to one side, in which case they occupy the entire height of the screen but only part of its width. They have no title bar, system menu, window borders or control buttons. Command interfaces like scroll bars are usually hidden at first. Menus are located in the "settings charm". Metro-style apps use the UI controls of Windows 8.x and typically follow Windows 8.x UI guidelines, such as horizontal scrolling and the inclusion of edge-UIs, like the app bar.

In response to criticism from customers, in Windows 8.1, a title bar is present but hidden unless users move the mouse cursor to the top of the screen. The "hamburger" menu button on their title bar gives access to the charms.

For most users, the only point of entry of Metro-style apps is Windows Store. Enterprises operating a Windows domain infrastructure may enter into a contract with Microsoft that allows them to sideload their line-of-business Metro-style apps, circumventing Windows Store. Also, major web browser vendors such as Google and Mozilla Foundation are selectively exempted from this rule; they are allowed to circumvent Microsoft guidelines and Windows Store and run a Metro-style version of themselves if the user chooses to make their product the default web browser.

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