Microsoft's preview of its Windows 10 developer strategy and universal app platform focuses on converging the platform across different form factors.

A blog post by Microsoft's Kevin Gallo, director of the Windows developer platform, detailed efforts in this vein at the Mobile World Congress conference in Barcelona. "Windows 10 represents the culmination of our platform convergence journey with Windows now running on a single, unified Windows core," Gallo said. "This convergence enables one app to run on every Windows device -- on the phone in your pocket, the tablet or laptop in your bag, the PC on your desk, and the Xbox console in your living room." Other devices, including the Raspberry Pi 2 board for Internet of things development, also will be supported.

The platform enables a class of "Windows universal apps," which are written once with one set of business logic and one UI. "[These are] apps that are able to reach every Windows 10 device the developer wants to reach," said Gallo.

Customers now prefer mobile experiences, Gallo noted. "Just a year ago, the experiences customers sought on Windows phones were different from tablet, which were different again from laptops and PCs and different from the game console. This has changed -- rapidly." Windows 10 is intended provide a new path for the "mobile experience," accommodating multiple screen sizes, but interaction models must be flexible as well, covering touch, mouse, keyboard, game controller, or pen, Gallo said.

In order to work across myriad devices, the platform includes adaptive UX, enabling the UI to fluidly adapt at runtime based on customer interaction and device capabilities; natural user inputs, incorporating speech, inking, gestures, and even user gaze; and cloud-based services, such as Windows Notification Services, Windows roaming data, and Windows Credential Locker. Windows shell advances, meanwhile, include Cortana integration, enabling apps to be launched from Cortana search results, and Action Center, for a more consistent notification experience for all Windows devices.

Gallo said that Windows 10 is intended to support existing Windows apps on their intended devices and the company is working to make it as easy as possible to move those apps to the universal app platform. For HTML developers, meanwhile, Windows 10 features a new rendering engine that delivers a "consistent" mobile experience and utilizes the Project Spartan browser.

Windows 10 will make it easy to build a Windows app that packages a website for publishing to the store. "Once installed, your website can update and call Universal APIs from JavaScript, creating a more engaging user experience," according to Gallo. The OS also will feature the first prototype of the Windows 10 Cordova platform in an Apache branch next month. Apache Cordova has provided a platform for building native mobile applications using Web technologies like JavaScript and HTML.