14 stable releases (6 major)

Uses new Rust 2024

7.0.0 Mar 22, 2026
6.0.0 Nov 12, 2025
5.1.0 Oct 6, 2025
4.1.0 Jul 24, 2025
1.0.0 May 17, 2023

#1351 in WebAssembly

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822 downloads per month
Used in 2 crates (via javy-plugin-api)

Apache-2.0 WITH LLVM-exception

61KB
1K SLoC

Javy

A configurable JavaScript runtime for WebAssembly

Documentation Status crates.io status

Uses QuickJS through the rquickjs crate to evalulate JavaScript source code or QuickJS bytecode.

Refer to the crate level documentation to learn more.

Example usage:

use anyhow::Result;
use javy::quickjs::{
   function::{MutFn, Rest},
   Ctx, Function, Value
};
use javy::{from_js_error, Runtime};

fn main() -> Result<()> {
    let runtime = Runtime::default();
    let context = runtime.context();

    context.with(|cx| {
        let globals = cx.globals();
        globals.set(
            "print_hello",
            Function::new(
                cx.clone(),
                MutFn::new(|_: Ctx<'_>, _: Rest<Value<'_>>| {
                    println!("Hello, world!");
                }),
            )?,
        )
    })?;

    context.with(|cx| {
        cx.eval_with_options("print_hello();", Default::default())
            .map_err(|e| from_js_error(cx.clone(), e))
            .map(|_: ()| ())
    })?;

    Ok(())
}

Publishing to crates.io

To publish this crate to crates.io, run ./publish.sh. You will likely need to run git submodule deinit test262 so the working tree is small enough for the publishing to succeed.

Dependencies

~9–13MB
~306K SLoC