The arena for programmers.
Two players. One problem. One clock. The server decides who won.
Get startedFree · Google sign-in · A match takes ten minutes
Matches need a keyboard. Sign up here and play at a desk.
Three steps, ten minutes.
No lobby to configure and nothing to install. From the queue to a decided result is one sitting.
- 01
Queue
Pick a language and a difficulty, then join the queue. You are matched with a real opponent, or a practice rival when the arena is quiet.
- 02
Solve
You both receive the same problem at the same moment. Run against the examples as often as you like; submissions are what count.
- 03
Win
First to pass every hidden test takes the match. Ranked results move your rating; the result is final the moment the server says so.
Fair by construction.
A race is only worth entering if the finish line is honest. These are the parts we refuse to leave to the client. Each one is a mechanism, not a promise.
Per-language limits
The same conditions
Identical problem, identical clock, identical limits. Python, JavaScript, Java and C++ each get time limits tuned to the language, so a correct answer is never punished for its runtime.
Server-authoritative
A clock you cannot argue with
The match clock, every verdict, and the result are decided on the server. Nothing your browser reports can change who won.
Withheld test data
Hidden tests stay hidden
You see how many cases passed and why one failed, never the test data itself. Nobody reverse-engineers their way to a win.
Isolated execution
Sandboxed judging
Every submission runs in an isolated sandbox with its own CPU and memory ceiling. Your opponent’s code cannot reach yours, and neither can reach us.
See how a race resolves.
Progress is public while the clock runs, so you always know how close it is. The test data behind that progress never is.
Decided at
4:12 / 10:00
6 / 6 hidden cases passed
3 / 6 hidden cases passed
Ten minutes. One opponent. Find out.
Solve under fair judging, protect your lead, and leave with a result that means something.
Free · Google sign-in · A match takes ten minutes
Matches need a keyboard. Sign up here and play at a desk.