The language every browser speaks

JavaScript Compiler Online — Run JavaScript Code in Your Browser

JavaScript runs in every browser and, via Node.js, on servers too — it's the one language you can't avoid if you're building for the web. Dynamic typing and a huge npm ecosystem make it fast to write, for better and worse.

function main() {
  console.log("Hello, world!");
}

main();

What people use JavaScript here for

• Testing a DOM-free algorithm or utility function without spinning up a project
• Trying out newer syntax (optional chaining, async/await patterns) before using it in real code
• Following a JavaScript tutorial without installing Node.js locally

No installs, no signup

Code you write here runs on a real, self-hosted Judge0 execution backend — actual JavaScript compiler or interpreter output, not a simulation. Node's actual version and V8 engine run your code here — no polyfills or transpilation hiding real behavior. See the full list of supported languages or read more about how AnyCompiler works.