Hexlet Battles

Codebattle is a game for coders! When the battle starts, you and your rival are given a programming puzzle. Solve it first and win!
Choose the weapon you like — your favourite programming language (currently Ruby, JavaScript, Python and PHP are supported). You can start a new game or join an existing one.

The game starts when both players are connected. Other users can join as spectators and discuss the game in real time using the built in chat. Players can use chat too, but they actually see each others’ code being written in real time, so they can communicate via comments in code. The best and most ruthless coders are displayed in the ‘Top’ ratings list.