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Introduction

Sway is a .NET library that renders Blazor components to a native desktop window — no browser, no WebView, no Electron. It hosts the standard Blazor component model and reimplements the pieces a browser would normally provide: an HTML/CSS parser, a style cascade, flex and grid layout, a Skia-backed painter, and OpenGL window with mouse/keyboard/IME input, all in C#.

App.Create()
   .AddStylesheet("app.css")
   .Run<MainWindow>("My App", 1024, 768);

A component in Sway looks exactly like a Blazor component, because it is one:

<div class="card">
    <h2>Count: @count</h2>
    <button @onclick="() => count++">Increment</button>
</div>

@code {
    int count;
}

Why Sway exists​

Blazor's component model (@code, data binding, event handlers, dependency injection) is a productive way to build UI, but it normally needs either a browser (WebAssembly) or a WebView (Blazor Hybrid). Sway instead lays out and paints that same component tree itself, so a Blazor UI can run as a self-contained native window with its own renderer — useful for desktop tools, kiosks, games and embedded UI where shipping a browser engine isn't desirable.

What's implemented​

  • A CSS parser and cascade covering selectors, specificity, @media, @keyframes and @font-face.
  • Block, inline, flex and grid layout.
  • Transitions, keyframe animations, gradients, shadows, filters and 2D transforms, all rendered through SkiaSharp.
  • A real OpenGL window (via Silk.NET) with mouse, keyboard, scroll and IME text input, plus a headless mode that renders straight to PNG for screenshot-based testing.
  • The built-in form controls (input, textarea, select, checkboxes, radios) with their own text editing and hit testing, since they draw themselves rather than laying out children.

None of this depends on a browser, WebAssembly or a WebView — see Architecture for how the pieces fit together.

What's not (yet)​

Sway is not a browser engine, and the gaps are tracked deliberately rather than discovered by surprise — see Known limits for the full list. The short version: no JS interop (so no Virtualize, InputFile, or most third-party Blazor component libraries), no routing, no accessibility tree, and a deliberately pared-down subset of CSS (no tables, no floats, no ::before/::after, approximate line boxes).

Next steps​