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Node.js 20 · free · no sign-up · input supported
Run modern JavaScript on Node.js 20, from one-liners to async code.
Run JavaScript in your browser on a real Node.js 20 runtime. Modern syntax such as classes, async/await, optional chaining and private fields work exactly as they do locally.
Because the code runs on Node rather than in the page, console output is captured cleanly and you can read test data from standard input.
ES2023 syntax, top-level timers, Promises and the built-in Node modules such as fs, path and crypto.
console.log, console.error and uncaught exceptions are shown in separate panels.
Read the Input panel with fs.readFileSync(0) or process.stdin to simulate judge input.
Node.js 20. There is no DOM or window object; use console.log for output.
No. Only Node's built-in modules are available in the sandbox.
The file runs as CommonJS, so use require(). Dynamic import() of built-in modules also works.
A few seconds of CPU time. Long timers or infinite loops are stopped and reported as a time-out.