Deno · version 2

Run Deno 2 online

Deno 2 — run it in a Firecracker microVM on ls-judge. Real toolchain, no wrapper.

Starter code

What you get in Deno 2

Clicking "Run now" opens the playground with this exact code and a matching test case — passes on first Run.

deno
Deno 2
const lines=[];
process.stdin.on('data',d=>lines.push(d));
process.stdin.on('end',()=>{
  const n=parseInt(lines.join('').trim());
  process.stdout.write((n*2)+'\n');
});
stdin →21
expected →42
How it runs

How ls-judge runs Deno 2

Every submission is compiled and executed inside its own Firecracker microVM — the same isolation primitive AWS Lambda uses. No shared container, no shared kernel with other users' code. The Deno 2toolchain shipped with the microVM is the real thing (not a browser-side emulation): syscalls behave the way they do in production, and the compile / runtime behaviour matches what you would see on your own machine with that version installed.

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