Run JavaScript. Straight in the engine.

Your own browser’s JS engine, in a Web Worker, so a runaway loop takes the worker and not the page. Worth saying plainly: this is not Node. There is no require, no fs and no process, so Node’s standard library is out of reach.

Nothing uploaded, nothing logged

runs in your tabYour browser's JS engine, in a Web Worker

console.log(`Hello from JavaScript, ES${new Date().getFullYear()}`);

const nums = [5, 2, 9, 1, 7];
console.log([...nums].sort((a, b) => a - b));

Tab indents · Shift+Tab dedents · Esc then Tab leaves the editor

Output

Output appears here. Press ⌘/Ctrl + ↵ to run.

Why this one never touches my server

The runtime is shipped to you and executed on your machine, so there is no endpoint to attack, no queue to wait in and no rate limit to hit. It also means I never see your code, which is the honest version of a privacy promise: not that I choose not to look, but that it never arrives.

Read the architecture