15 July 2026
Raku.js — Raku now runs in your browser
Two days ago we introduced Raku++, our new Raku compiler. Today, meet its little sibling with a big trick: Raku.js brings the Raku programming language straight into your web browser.
Try it right now, nothing to install: course.raku.org/playground.
What it is
Raku.js is the Raku++ interpreter compiled to WebAssembly. It is not a rewrite in JavaScript — it is the exact same engine that powers the native compiler, so the code you run in the browser behaves exactly like the code you run in your terminal.
Everything happens on your machine, in the page itself:
- No server round-trips — your program runs locally, instantly, even offline once the page is loaded.
- A responsive playground — the interpreter runs in a Web Worker, so the editor never freezes; you get live output and a Stop button that actually stops.
- Tiny footprint — the whole playground is five static files, about 4 MB, and can be embedded into any website.
Where you will meet it
Raku.js powers the instant playground of the Raku Course, where every example can be edited and executed right on the page. It is the fastest way there is to try Raku: open the page, press Run.
Open source
Raku.js is part of the Raku++ project on GitHub: github.com/ash/rakupp. If you want runnable Raku examples on your own site, the playground drops into any static page.