Building a Cross-Platform Desktop App with Avalonia UI and C#

One of my freelance projects needed a desktop app that had to run on Windows, macOS, and Linux without maintaining three separate codebases. After trying a few options, I settled on Avalonia UI with C#.

Avalonia feels a lot like WPF in terms of XAML and data binding, so if you’re already comfortable with .NET, the learning curve isn’t too steep. The difference is that Avalonia is genuinely cross-platform — one codebase, rendered itself on each OS via Skia, so the UI stays consistent without needing native controls per platform.

What I like: hot reload for previewing the UI, CSS-like styling through XAML, and an active community, even if it’s smaller than Electron’s or Flutter’s. The downside is documentation for advanced cases (custom rendering, native interop) is still thinner than more mainstream options.

For my case — a desktop app that needed low-level access (VPN connections, security reporting) while still having a pleasant UI — Avalonia plus C# turned out to be a good fit. No browser runtime like Electron, and performance is much lighter.

If you’re looking for a genuinely cross-platform alternative to WPF, it’s worth trying.