Chrome ExtensionPlay Mastermind with AI for Free
A pure deduction duel. You and the AI race to crack the same secret 4-peg code, taking turns, each with private feedback. Ten guesses each, first to four exact pegs wins. Three free games every day, no signup needed.
Opponents
80+ live AI models
Modes
Race vs AI · Watch AI vs AI
Price
Free, 3 games/day
Platform
Browser, no signup
Set Up Your Game
Free: 3 games per day. No signup needed.
How to Play Mastermind Against AI
One secret, two solvers
The server generates a hidden code of 4 pegs from 6 colors (repeats allowed). You and the AI both try to crack it.
Read the feedback
After each guess: a black peg means right color in the right spot, a white peg means right color in the wrong spot.
Crack it first
Guesses alternate, you go first. Ten guesses each. The first side to hit all four exact pegs wins the race.
Frequently Asked Questions
How good are AI models at Mastermind?
Genuinely good. Mastermind is logical deduction, which is a strength of modern models. Most codes fall in 4 to 7 guesses, so you will need sharp logic to beat them.
Is playing really free?
Yes. Everyone gets three free games per day across all our AI games. No signup, no credit card, no downloads. The limit resets every 24 hours.
Can the AI see my guesses?
No. Each side only sees its own guesses and its own feedback, exactly like sitting on opposite sides of the table. The server holds the secret and scores both of you independently.
Which AI models can I race?
The model list is fetched in real time from OpenRouter, including GPT, Gemini, Claude, Grok, DeepSeek, Qwen, Llama and more. New models show up automatically as they are released.
What is the best strategy?
Open with two pairs of colors to split the space, then only make guesses that are consistent with every clue you have received. Consistency is the whole game.
Out-deduced the deduction machine?
Learn to get exactly what you want from AI models. 20,000+ premium prompts, custom GPTs and courses inside the Promptslove members area.