Infinite XO
A two-player XO game where each player keeps only their three newest marks.
Start a game
- A registered player can create a room for another player. Registered players and guests can start an unrated match against the bot.
- A second signed-in player joins from the lobby or shared room link.
- Before play begins, the host may use Kick on the other player's card. That player cannot view or rejoin the room, and another player may take the open slot.
- The second player marks themselves ready. The creator is ready by default, and either player can change their ready status before play begins.
- Once both players are ready, the host starts the game. The server randomly assigns X and O, and X takes the first turn.
Bot matches start immediately, appear publicly for other viewers, and do not affect ELO. Guests may also view other Infinite XO rooms. The bot takes a winning move when available, blocks an opponent's immediate winning cell otherwise, and falls back to a random unoccupied cell.
Take a turn
Place your symbol in any empty cell. Players alternate turns, and a move cannot be placed on an occupied cell.
You can click an empty cell, or use the arrow keys to select a cell and press Space to place your mark.
Your marks are ordered from newest to oldest. When you place a fourth mark, your oldest mark disappears immediately. The glowing mark shows which of your marks will disappear on your next turn.
Win the game
You win by keeping three of your marks in one horizontal, vertical, or diagonal line. A win is checked only after any required oldest-mark removal, so a line that is broken by that removal does not win.
Ratings and leaving
In a two-player room, a three-in-a-row win updates both players' Infinite XO ELO. During an active game, either player may confirm Resign; the opponent wins, both ratings are updated, and the resigning player remains in the completed room. Choosing Exit Room during an active game also gives that player a loss and updates both ratings, then returns the exiting player to the lobby. Matches against the bot are unrated. Leaving a waiting room has no rating effect. Spectators may watch but cannot place marks or resign.