Kael

GPU-accelerated UI framework for native desktop apps in Rust.

Kael replaces Electron with a single Rust crate that gives you everything you need to build production desktop applications — IDEs, video editors, dashboards, design tools — with native GPU performance on macOS, Windows, and Linux.

What you get

Quick start

Add to your Cargo.toml:

[dependencies]
kael = "0.1"

Write your first app:

use kael::*;
use kael::prelude::*;

struct Hello {
    name: SharedString,
}

impl Render for Hello {
    fn render(&mut self, _window: &mut Window, _cx: &mut Context<Self>) -> impl IntoElement {
        div()
            .size_full()
            .flex()
            .items_center()
            .justify_center()
            .bg(rgb(0x1E1E1E))
            .text_xl()
            .text_color(rgb(0xFFFFFF))
            .child(format!("Hello, {}!", self.name))
    }
}

fn main() {
    Application::new().run(|cx: &mut App| {
        let bounds = Bounds::centered(None, size(px(400.0), px(300.0)), cx);
        cx.open_window(
            WindowOptions {
                window_bounds: Some(WindowBounds::Windowed(bounds)),
                ..Default::default()
            },
            |_, cx| cx.new(|_| Hello { name: "World".into() }),
        ).unwrap();
        cx.activate(true);
    });
}

Native rendering quality

Kael renders with the same sharpness as first-party platform apps:

• macOS: SF Pro Text/Display optical sizing (automatic swap at 20pt), sRGB Metal pipeline, continuous (squircle) corners matching SwiftUI, AppKit-matched font smoothing
• All platforms: PixelSnapPolicy for hairline strokes, device-pixel-aligned text baselines, and crisp fills at any DPI

Platform support

Acknowledgements

Kael is built on top of GPUI, the GPU-accelerated UI framework originally created by Zed Industries for the Zed code editor. We are grateful for their foundational work which made Kael possible.