WebAssembly

Burn supports WebAssembly (WASM) execution using the NdArray and WebGpu backends, allowing models to run directly in the browser.

Check out the following examples:

• Image Classification Web
• MNIST Inference on Web

When targeting WebAssembly, certain dependencies require additional configuration. In particular, the getrandom crate requires explicit setting when using WebGpu.

Following the recommended usage, make sure to explicitly add the dependency with the wasm_js feature flag for your project.

[dependencies]
getrandom = { version = "0.3.2", default-features = false, features = [
    "wasm_js",
] }

You also need to set the getrandom_backend accordingly via the rust-flags. The flag can either be set by specifying the rustflags field in .cargo/config.toml

[target.wasm32-unknown-unknown]
rustflags = ['--cfg', 'getrandom_backend="wasm_js"']

Or by using the RUSTFLAGS environment variable:

RUSTFLAGS='--cfg getrandom_backend="wasm_js"'

This change is now explicitly required with latest versions of Burn, following the getrandom recommendations. This avoids potential issues for WASM developers who do not target Web targets.