Microsoft Project Reunion unifies Win32 and UWP apps on Windows 10

Microsoft is combining Win32 and UWP with Project Reunion to allow developers to easily build modern apps for 1 billion devices running Windows 10.

Microsoft Project Reunion (source: Microsoft)
Microsoft Project Reunion (source: Microsoft)

Microsoft is announcing Project Reunion, the latest attempt to unify the development of traditional desktop apps (Win32) and Universal Windows Platform (UWP) apps to build universal apps that run across multiple devices running Windows 10.

Also, as a result of this new unification, the software giant is now referring to Win32 and UWP apps as “Windows apps.”

Originally, Microsoft created the Universal Windows Platform as a new way to build apps on Windows 10, but the idea never gained popularity among developers, and since most people still running older versions of the operating system, developers continued to use the Win32 platform, which isn’t a modern approach to create apps.

The idea of Project Reunion is to allow developers to code one app that will run on any device running Windows 10 without having to choose between Win32 and UWP APIs, since the platforms are now unified, and they’re now separated from the operating system.

Also, since the APIs are not longer part of Windows 10, developers can now access the open-source package manager NuGet to pull the new APIs to compile the apps without worrying about older releases of the operating system.

In the past, developers would have to wait until a new version of Windows 10 was available before they were able to update their apps.

One significant part of this new project is WinUI 3, which is a UI framework that allows to transform applications with a modern user interface that can scale across devices.

If a developer has already an app, with Project Reunion, they can update and modernize the existing code to take full advantage of the features available on Windows 10.

Alongside these changes, Microsoft is also introducing a preview of WebView2, which is a control that enables developers to include Chromium-based web technologies (HTML, CSS, and JavaScript) in their native apps.

In addition, WebView2 will also be soon be separated from the operating system to allow developers to take full advantage of the web technologies without having to worry about versions of Windows 10.

About the author

Mauro Huculak is a Windows expert and the Editor-in-Chief who started Pureinfotech in 2010 as an independent online publication. He is also been a Windows Central contributor for nearly a decade. Mauro has over 12 years of experience writing comprehensive guides and creating professional videos about Windows, software, and related technologies, including Android and Linux. Before becoming a technology writer, he was an IT administrator for seven years. In total, Mauro has over 20 years of combined experience in technology. Throughout his career, he achieved different professional certifications from Microsoft (MSCA), Cisco (CCNP), VMware (VCP), and CompTIA (A+ and Network+), and he has been recognized as a Microsoft MVP for many years. You can follow him on X (Twitter), YouTube, LinkedIn and