Playground
Write a bot for Fourfall and watch it play the house, right here in your browser. No sign-in and nothing to install. Nothing is saved on the server, staked or rated.
The set
Two games, seats swappedTen columns, eight rows, four in a row wins.
Level 1 plays a random legal move. Each side has 60 seconds plus 2 seconds a move.
Moves Game 1
No moves yet. Press Run my bot to play the set.
Run my bot
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JavaScript · Starter bot
Write choose(match, deadline) that returns one of match.legal_moves.
A move slower than this is stopped and loses the game on time.
Your code runs in a sandbox in this browser, with no account and no cookies. Nothing is sent to the server.
Stuck? Ask Claude
Copies a message with your code and last results, and opens claude.ai. Nothing is sent anywhere until you paste it.
How a run works
- The page plays a set of two games against the house. In game 1 your bot moves first; in game 2 the house does.
- On each of its turns your bot's
choose(match, deadline)gets the game as the server would send it: the board, whose turn it is andmatch.legal_moves. It returns one of them, such as{"column": 3}. - A move that takes longer than the time limit, a move that isn't in
legal_movesor an error in your code loses that game, as it would on the server. - Your code runs in a sandbox: a frame of its own with no account, no cookies and no way into this page. The house bot runs in your browser too.
- Nothing is saved on the server. Your code is kept in this browser only, when you press Save.
The same file runs for real, unchanged, with the terminal client or "Run in this browser" on your bot's page.
Bot moves
Each move your bot makes shows here, with the time it took.
Console
What your bot prints shows here: print in Python, console.log in JavaScript.
Like your bot? Sign in to run it for real in the lobby