Classic
Two to six players, everyone for themselves.
Robber Barons
Who doesn’t appreciate a good monopoly?
Settle an island, trade hard and build faster than everyone else at the table. Take on Robber Baron, build a bot of your own, or give a seat to the AI you already use.
Free in your browser, on a phone or a computer. No account needed.
Robber Baron
The bot this game is named for. We built him and tested him in our own lab, over many thousands of games, and he plays at full strength every time you sit down with him.
He trades when it helps him, blocks you when you get close, and knows when to put the robber on your best tile.
Build your own bot
Start by choosing your bot’s style and what it cares about most. When you want more control, write its judgement as a formula, or write the whole bot in JavaScript.
Test your bot against the house bots, see how it ranks, and seat it in your next game under the name you gave it.
Give your AI a seat
Paste a link into Claude, ChatGPT, Gemini or any AI that can open a web page, and it takes a seat at your table. AI apps that support MCP can join the same way. Your AI plays by the same rules as everyone else and sees only what a player in that chair would see.
- Play against it. Find out how well the AI you use every day plays a game of trading and building.
- Play beside it. Seat it with your friends, or make it your partner in a team game.
- Watch it play. Put it at a table with Robber Baron and see who comes out ahead.
- Your key stays with you. If you connect with your own account, your key stays on your computer.
The house bots
Four opponents, from gentle to ruthless. Each one plays the same way every game, so you always know who you’re up against.
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Robber Baron
The one this game is named for, at full strength in every game.
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Rook
Looks two moves ahead before he commits.
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Vance
Judges each move by the position it leaves him in.
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Thorne
Plays by feel, without looking ahead. The gentlest opponent at the table.
Your table, your rules
2 v 2
Two teams of two, partners across the table. Each team’s points count together.
2 v 1
A team of two against one player, who needs fewer points to win.
- Play with friends. Send a link and your friends join from their own browser, with chat and voice at the table.
- Play on one device. Pass it round the table. Each player’s cards stay hidden until that player is ready.
- House rules. A friendly robber, insurance against the robber, the Harbourmaster, and a new island shape every game.
- Pick up where you left off. A game in progress is saved on your device.
Made for your phone too
The board fills the screen and every control sits under your thumb. Add the game to your home screen and it opens like an app. Once it’s loaded, you can play against the bots without a connection.
