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Coding duels

Queue by rating or open a private room, race an opponent on a problem or bug hunt with both sides live, and let the judge settle it. Wins pay XP and rating.

What is a CodeKairo coding duel?

A duel is a live race on a random problem or bug hunt, 1v1 or 2v2: the first accepted submission wins for its side, and there is no second place. The public queue seats you with the first waiting duel within ±200 rating, widening by 100 every ten seconds; a private room is a six-character code and starts when everyone has pressed Ready. Both sides see the other's activity live — running, tests passed, submitting. The clipboard is locked, leaving the tab hides the board, and the third strike disqualifies. A win from the public queue pays 40, 60 or 90 XP by difficulty with a third of it to rating, and the losing side keeps 25%; private rooms pay no XP or rating. Unlimited on every plan.

How it works

  1. Pick a mode. 1v1 or 2v2, on a problem or a bug hunt. The arena is drawn when the fight starts and is never one a seated player has already solved.
  2. Queue, or share a code. The public queue matches by rating and widens while you wait, and its wins pay XP; a private room takes friends by code, starts when everyone is Ready and pays nothing.
  3. Race to Accepted. You see the other side run, pass tests and submit; they see you. Wrong answers cost nothing but time. The judge settles it the instant an accepted submission is written.
  4. Read the winning code. After the bell, both sides can open the winning submission — the code, or the files the winner changed for a hunt. The page keeps your last ten duels and the record across them.

Who it is for

People who solve faster with someone across the table — and pairs of friends who have argued about who is quicker and would like the judge to settle it.

Frequently asked questions

How are opponents matched?
In the public queue you are seated in the first waiting duel of the same mode within ±200 rating; the band widens by 100 every ten seconds until someone fits. Private rooms use a six-character code and start once everyone has pressed Ready.
What decides the winner?
The first accepted submission on the problem or bug hunt, wherever it was made. There is no time limit, so a hard problem can take as long as it takes. If your opponent leaves and does not come back within two minutes, you can claim the win.
What about cheating?
The clipboard is locked, switching tabs or apps hides the board, and screenshot shortcuts are refused. Each attempt is a strike; being away for more than three seconds is a strike; the third strike disqualifies you and the other side wins.
What does a win pay?
In a duel from the public queue: easy 40, medium 60 or hard 90 XP to the winning side, and a third of that to rating. The losing side keeps 25% as consolation. Walking away hands the other side 50%. Private rooms pay no XP or rating — they are for playing friends, not for the ladder. Duels are unlimited on every plan.