The JavaScript host and transpiler for WebAssembly components — run any component in Node.js or the browser.
Jco is the Bytecode Alliance toolchain for running WebAssembly components in JavaScript environments. It transpiles a component's WIT-described interface into idiomatic JavaScript and TypeScript bindings, then executes the component in a Node.js or browser host via the Wasm component-model runtime. The 1.24.1 release (June 16, 2026) tightens WASI 0.2 support and improves component composition workflows, making it the standard way to consume components from JS today.
Package Python libraries and applications as WebAssembly components — a Component Model story for the Python ecosystem.
Turn JavaScript and TypeScript code into WebAssembly components — JS that speaks WIT to the rest of the world.
A fast, secure WebAssembly runtime built by the Bytecode Alliance with full WASI 0.2 and Component Model support.