XAML.io is an impressive web-based software development IDE that lets you build C#/XAML .NET apps using a prompt. It’s free to try, there’s no sign-up, and there’s nothing to install.
“XAML.io v0.9 adds an AI coding agent that writes, builds, and fixes C# and XAML,” the XAML.io team writes in the announcement post for the latest release. “It also adds one-click Web publishing and Version History, and it shows what every AI request costs, in dollars. Every project is a standard .NET solution. You can keep changing it with the agent, in code, or in the visual designer, or open it in Visual Studio.”
XAML.io is built on top of the OpenSilver open source framework that was designed, in part, to bring legacy .NET apps–including WPF and Silverlight apps–to the web. It runs WPF-style C#/XAML apps in the browser using WebAssembly and MAUI Hybrid and Photino to run these apps natively on mobile devices.
Like other AI prompt-based coding tools, XAML.io lets you describe an app using natural language and then uses an AI agent to write and compile it while fixing any errors that pop up. When the app is complete, you can publish it to the web or open it in Visual Studio. AML.io is free, as noted, but you will need to pay for AI usage; you get $5 per month in free AI usage and there’s a XAML.io Pro subscription for $20 per month that provides $20 of AI usage.
What sells this solution is the set of fun demo apps that XAML.io provides, including a full-featured version of Microsoft Paint as it appeared in Windows 98. This was made using the simplest-possible prompt–“Build a Paint clone as it appeared in Windows 98”–and the (GPT-6 Astra) AI agent created it in 42 minutes, XAML.io says, in 3500 lines of C# and XAML code at a cost of $57. You can open this project and the other examples in XAML.io and see it for yourself. And then you can edit it as desired.
This looks incredible, and its Migrate from WPF functionality obviously has me thinking. I will dive deeper into this soon.