One secret code, and the whole room guessing at once. Every guess is graded privately, on the guesser's own phone, and the first person to crack it wins outright.
Mastermind, minus the shared board. Nobody can lean over and read your deductions, so your phone is the only place your progress ever shows. Play it around one table or with a room scattered across the country.
Only you can see this. Use it to narrow your next guess.
What actually happens
The room goes quiet. Everyone is on their own phone, working their own trail, because nobody's board looks like anyone else's. First guess goes in: 1234. The feedback lands back on that one screen only: one right, two in the wrong place.
Across the room, ten other phones are running ten different trails. Someone tries 4321. Someone else tries 5678. There is nothing to lean over and copy, so everybody is actually thinking. Someone is scribbling on a napkin. Somebody else has quietly opened a spreadsheet.
By the seventh guess, one person leans back, smiles, and submits 8462. Four correct, none misplaced. The room only finds out when every screen changes at once: somebody cracked it, and the game is over.
The rules
The host chooses a code of four, five or six digits, a round timer and Easy or Hard feedback.
Everyone submits one full-code guess on their own device before the round ends.
When the timer ends or the host grades early, read your feedback and compare it with your earlier guesses.
The next round uses the same code. Keep narrowing the possibilities until someone submits the exact answer.
The first correct submission to reach the host wins when guesses are graded. Partial guesses earn no points, and there is no running leaderboard.
Digit-by-digit feedback
Easy mode colour-codes every digit, not just a tally
Two feedback modes
Easy shows you which digits landed, Hard only tells you how many
Private deduction
Everyone works from their own guesses, nobody sees anyone else's
First correct guess wins when the round is graded
While you host
Choose the challenge before play, then manage each guessing window from the host dashboard.
Example final podium
Ada
1,000
Example result: one winner for a solved code
Choose four, five or six digits and a timer of 30, 45 or 60 seconds. Generate a random code or enter your own before selecting Lock In and Start.
The host view shows who has submitted and keeps the code covered. Feedback appears on each player's own board; leave the code hidden while the audience can see your screen.
Use Grade Guesses to close a round early, or let its timer finish. Next Round keeps the same puzzle; Restart with a New Code clears all deductions.
Give each player a device and space to read their guess history. Paper for notes helps people compare possibilities between rounds.
Choose the code before sharing your host window, then keep it covered. Explain the feedback key before starting the first timer.
Let everyone see the shared timer. Leave a pause between rounds for players to read their feedback before opening the next guessing window.
Use cases
Make space for a puzzle that rewards testing an idea and learning from the result.
Team offsites and virtual socials
Between workshop sessions, put one code in front of an engineering or analyst team. Everyone follows their own trail of guesses and submits individually. After the reveal, compare the experiments that helped each person eliminate possibilities.
Find games for team socialsPub quizzes and family nights
Break up a quiz with a challenge that does not depend on knowing the right fact. Start with four digits and Easy feedback while everyone competes individually. The changing guess history gives players something to work with even when their first attempt is nowhere close.
Add games to a pub quizClassrooms and workshops
Use the longer timer to give learners time to record a prediction before submitting. Once the code is solved, ask them to explain which guess taught them most. Switch to Hard feedback for a later game that requires interpreting counts without digit-by-digit clues.
Explore facilitated activitiesFeedback settings
Every player uses their own device and sees their own guess history. Crack the Code requires a session in player mode.
See feedback on each digit.
Symbols and colours show which digits are correct, misplaced or unused. Your board also lists digits your guesses have ruled out.
Best for
a first game or a shorter puzzle.
Work from the totals.
See how many digits are correct and how many are misplaced. You work out which ones they are by comparing your guesses.
Best for
players who want a tougher deduction challenge.
Before you start
More about hosting? Visit the help center.
