Two developers.
One problem.
One clock.
Code Clash pairs you with a developer at your rating and drops you both into the same algorithm problem. First to pass every hidden test takes the points.
Queue to rating change in about twenty minutes.
- 01
Join the queue
Open the arena and enter ranked matchmaking, or pick a problem and practice solo first.
- 02
Get paired
You are matched with a developer inside your rating bracket, and you both receive the same problem at the same moment.
- 03
Race the tests
Write your solution while their verdicts stream in beside yours. You see how close they are, never what they wrote.
- 04
Take the rating
First to pass every hidden test wins the duel and the points. Your tier follows your rating up the ladder.
Find out what a win is worth.
Drag the ratings. Every figure below is computed by the same Elo function the server runs when a duel settles — nothing here is illustrative.
A win puts you at 1261 (Silver), a loss at 1229 (Silver). Beating someone above you pays more than beating someone below. The opponent slider is limited to 1047–1447 because the queue opens at ±200 around your rating, widening to ±600 the longer nobody turns up.
Everyone starts at 1000.
Six tiers, one rating. These are the real thresholds the server checks after every duel — there is no soft reset and no way to buy a rank.
Bring whatever you think in.
JavaScript and TypeScript execute in a sandboxed Web Worker on your machine, so they return instantly. The rest compile remotely.
Built like a judge, not a course.
Matched on rating, not luck
The queue pairs you inside a 200-point ELO bracket, so every duel is winnable and every win is earned.
The editor you already use
Monaco — the same core that runs VS Code — with autocomplete, multi-cursor, and the keybindings already in your fingers.
Hidden tests decide it
Every problem ships visible examples plus hidden edge cases. Passing the samples is not passing.
Settled server-side
Elo at K=32, computed on the server the moment a duel ends. Nothing about your rating is negotiable.
Free, with no card
Every problem, every ranked duel, and the whole leaderboard. There is no paid tier to lose to.
Go take someone's rating.
Create an account, get your starting 1000, and find out where you actually land.
Create your account