wasm-bridge

Goals

The goal of this crate is to "run wasmtime on the web", that means providing a unified API for desktop and web runtimes.

With wasm-bridge, you can write a single source code in Rust that you would normally write when using wasmtime, but it works on desktop as well as on the web.

How do I use this?

In general, you would use this crate the same way wou would use wasmtime, and just replace wasmtime with wasm_bridge.

Alternatively, refer to this handy table:

Use case	📝 Text tutorial	▶️ Video tutorial	🧾 Full example	📑 Test cases
No bindgen	Read here	Coming soon	See here	Explore here
Component model	Read here	Coming soon	Coming soon	Explore here
Component model with WASI	Coming soon	Coming soon	Coming soon	Explore here

Versions

wasm-bridge	wasmtime	wit-bindgen	cargo-component
0.5.x	20.0	0.24.0	0.11.0
0.4.x	19.0	0.24.0	0.10.1
0.3.x	15.0	0.15.0	0.5.0
0.2.x	11.0	0.8.0	-
0.1.x	10.0	-	-

Alternatives

There are other options for loading and executing WASM modules on the desktop and on the web in RUST: wasmer can run on the web with the js feature flag, wasmi is an interpreter so it has no problem running on the web, and wasm_component_layer provides a unified API that can be "backed" by a number of "backends".

Crate	Short description	Component model	Wasi support
wasm-bridge	Re-exports wasmtime on sys, js-sys impl on web.	Yes, but no resources.	Partially yes.
wasmer	Native impl in sys, js-sys impl on web.	They have wai bindgen.	Yes.
wasmi	Lightweight WASM interpreter, run anywhere.	Planned.	Experimental wasmi_wasi crate.
wasm_runtime_layer	Thin wrapper around wasmtime or wasmi, js-sys impl on web.	wasm_component_layer, but no bindgen.	Not to my knowledge.

License

The source code of wasm-bride is licensed under MIT, but there are portions that are copied from other projects, and may come with a different license.

Here is a full list of these exceptions:

• The wasmtime-component-macro crate "fork".