Build spatial and XR applications in Rust with a RealityKit-inspired API. Write once, run on native (macOS/Windows/Linux) and web (WebGPU/WebXR).
// lib.rsuse fastn::{ModelEntity,MeshResource,SimpleMaterial,RealityViewContent};#[fastn::app]fnapp(content:&mutRealityViewContent){let cube = ModelEntity::new(MeshResource::generate_box(0.5),SimpleMaterial::new().color(0.8,0.2,0.2));
content.add(cube);}// main.rsfnmain(){
fastn::main();}cargo run # Run native shell (default)
cargo run -- build # Build for web (creates dist/)
cargo run -- serve # Build and serve web versionmy-app/
Cargo.toml
src/
lib.rs # Your app code with #[fastn::app]
main.rs # Just calls fastn::main()
assets/ # Optional: GLB models, textures, etc.
index.html.tmpl # Optional: custom HTML template
[package]
name = "my-app"edition = "2024"
[lib]
crate-type = ["cdylib"]
[[bin]]
name = "my-app"path = "src/main.rs"
[dependencies]
fastn = { git = "https://github.com/fastn-stack/spatial" }Create index.html.tmpl in your project root to customize the web shell:
<!DOCTYPE html><html><head><title>{{APP_NAME}}</title><!-- Your custom styles --></head><body><canvasid="canvas" data-wasm="{{WASM_FILE}}"></canvas><!-- Standard shell scripts --><scriptsrc="shell-common.js"></script><script>// Platform detection and initialization</script></body></html>Available placeholders:
{{APP_NAME}}- Your crate name{{WASM_FILE}}- Path to the WASM file (includes hash for cache busting)
See the examples/ directory:
- cube - Simple red cube using programmatic mesh generation
- cube-glb - Loading a 3D model from a GLB file
Run an example:
cargo run -p cube # Native
cargo run -p cube -- build # Web- fastn - Core API crate (RealityKit-like types and #[fastn::app] macro)
- fastn-cli - CLI tools embedded in fastn (build/serve/run commands)
- fastn-shell - Native runtime (WebGPU + wgpu)
- fastn-shell-web - Web runtime (WebGPU or WebGL+WebXR)
MIT OR Apache-2.0