Code Battle

Code Battle turns Codeforces into a head-to-head arena. ⚔ Two players, real Codeforces problems Race a friend in a private room, or queue for a ranked match against a Codeforces user within ±500 of your rating. First Accepted submission takes the round. Best of 3 wins the match. Everything happens on one page The problem and the official Codeforces editor are embedded side by side inside Codeforces' own /battle page. No tab switching, no copy- pasting, no leaving the site you already know. Ranked leaderboard with Elo Verify your handle once with your Codeforces API key and your ranked matches will count toward a global Elo leaderboard. Friend-room games are casual and do not affect rating. Privacy-first opponent view You can see that your opponent is coding — typing pulses, line count, caret position — but you never see what they are typing. The "ghost code" preview is generated locally from a hash of their handle; their real source code never leaves their browser. What it does NOT do - Does not read or upload your source code - Does not share data with third parties - Does not require your Codeforces password (API key signing only) - Does not track your browsing history Open https://codeforces.com/battle after installing. Made by Reza Shiri. Not affiliated with or endorsed by Codeforces.