XAML.io Has Released Web-Based C# IDE Update
The new version 0.9 integrates an AI agent capable of writing, building, and debugging code directly in the browser.
Updated on Sept. 21, 2026 in Software
Live Poll
Would you use an AI agent to build and maintain your own software applications?
XAML.io has released version 0.9 of its web-based integrated development environment, adding an AI coding agent for C# and XAML projects. The platform leverages the OpenSilver framework to run applications within browsers using WebAssembly.
Why it matters
By enabling browser-based compilation of C# and XAML applications, this release lowers the barrier to entry for desktop-style development. The integration of an AI agent aims to automate the build-and-fix cycle for developers working within a unified web environment.
The v0.9 platform features an AI agent that generates code based on natural language prompts. The service provides $5 in free monthly AI credit, while the $20 per month Pro subscription includes $20 in AI usage.
The players
XAML.io
A web-based integrated development environment platform focused on C# and XAML workflows.
OpenSilver
An open-source framework that enables the execution of XAML-based applications in modern web browsers.
Visual Studio
A comprehensive integrated development environment developed by Microsoft for software engineering.
The details
XAML.io utilizes the OpenSilver framework, an open-source implementation of Silverlight that enables C# and XAML apps to run in browsers using WebAssembly — a binary instruction format for a stack-based virtual machine. The AI coding agent handles the generation and compilation of code, allowing for one-click web publishing. Finished projects are compatible with Visual Studio for further refinement or local development.
Timeline
September 21, 2026: XAML.io released version 0.9.
The Tech Race
XAML.io is positioning its platform to modernize C# development workflows that historically relied on desktop-bound tools like the Microsoft Silverlight framework. By utilizing WebAssembly, it aims to displace traditional plugin-heavy environments with a browser-native stack.
Developers can begin using the v0.9 tools immediately through the web-based interface. The free tier offers $5 in monthly AI credits, while the Pro tier provides $20 of usage, though full production-readiness for complex enterprise apps remains to be verified by individual users.
The takeaway
The move toward browser-native C# compilation signals a shift in how lightweight web apps are architected and deployed. Users should monitor whether the AI agent's performance in the 42-minute Paint clone demo holds up across more complex, proprietary enterprise codebases.
Further reading
For more background on browser-based development tools, see the Software section.
Live Poll
Would you use an AI agent to build and maintain your own software applications?
