R
Ranked
Join the queue and put your rating on the line. Rating only ever moves in Ranked.
Analyse, outsmart, crack the code
One secret code.
Everyone races
to crack it.
guessIo is a multiplayer code-breaking game. Every player guesses the same hidden code, reads the colour feedback, and the first to solve it wins the round. The match lasts up to three rounds.
Free to play · Practice needs no account ·
Phone or desktop
ANALYSE
OUTSMART
CRACK IT
OUTSMART
CRACK IT
One code. Everyone races.
2 to 4 players per online match✳Best of 3 rounds decide the match✳30 s default turn timer✳Free practice needs no account
Level 01 · Walkthrough
How to play,
step by step.
Press Next to move through a worked example. Each stage shows how one round is read, from the secret code to the colours.
How to playStep 1 of 4
Difficulty
Same guess. Different feedback.
STANDARD · WIN = 3 POINTS
Green marks a digit in the right place. Amber marks a digit that is in the code but belongs somewhere else.
HARDCORE · WIN = 5 POINTS
Right place is hidden. Every digit in the code shows amber, so you work out the slot yourself.
Level 02 · Ways to play
Pick how much
is on the line.
Online matches support two, three or four players. A bigger table means a longer code and a bigger guess budget.
C
Casual
Same queue, no rating risk. A relaxed way to learn the clues and still earn points.
Cu
Custom
Create a room, share its code with friends and play privately. The host can start once every seat is filled.
P
Practice
Play against the system, or pass and play with a friend on one device. No account or turn timer is needed.
Level 03 · Table size
Table size
sets the code.
Practice lets you choose Easy, Medium or Hard. Online, the number of players determines the code length and guess budget.
| Players | Code length | Guess budget |
|---|---|---|
| 2 | 4 digits | 10 guesses |
| 3 | 5 digits | 15 guesses |
| 4 | 6 digits | 20 guesses |
Level 04 · Progression
Two numbers.
Two leaderboards.
Points are earned from completed Casual and Ranked matches. Rating changes only in Ranked. They are tracked and ranked separately.
Points
Earned at the end of every completed Casual or Ranked match.
| Result | Standard | Hardcore |
|---|---|---|
| Win | +3 | +5 |
| Draw | +1 | +1 |
| Loss | 0 | 0 |
Every new account starts at 0 rating and 0 points.
Rating
An Elo style score. In Ranked, every pair of players is compared by final placement and the results are averaged. Bigger tables move your rating further, because more is at risk.
Matchmaking is first come, first served, not skill based. Hold a top 10 rating position with at least 10 Ranked matches and a Top 10 status shows on your profile.
Achievements
Permanent badges on your profile.
01Welcome to guessIoPlay your first match.
02NewbieWin your first match.
03SpeedsterWin a round in under 1 minute.
x5Flawless x5Win 5 matches in a row.
Level 05 · Before you jump in
Questions players
ask first.
Do I need an account?
Not for Practice. Play the system or pass and play with a friend with no sign-up. An account, created with Google sign-in, unlocks Casual, Ranked, private rooms, leaderboards and match history.
Why do I have to sign in every time?
For account security, your session is tied to your browser tab and is destroyed the moment the tab closes, so a new tab means a fresh sign-in. Refreshing the page keeps you signed in. On mobile, your session may persist: the app may keep you signed in until you log out or your session expires. Either way, an account can only be signed in on one device at a time, so signing in somewhere else ends your previous session.
Does everyone get their own secret code?
No. There is exactly one secret code per round, shared by the whole table, in 2, 3 and 4 player matches alike. Nobody is guessing anyone else's personal code.
Why can't I see my opponents' colours?
Feedback is private. You see the digits your opponents guessed, but only the player who guessed sees what colours it earned. Study their guesses to work out what they might know.
What if I disconnect or stop playing?
You get a 60 second window to reconnect and drop straight back in. After that you forfeit. If a full rotation passes twice in a row with nobody guessing, the match is cancelled and everyone left takes a 30 point rating penalty and loses 10% of their points.
Is guessIo free?
Yes. Playing never requires payment.
What can I play it on?
Any modern browser on desktop or mobile. You can also install it from your browser menu using Install app or Add to Home Screen, or download the mobile app, so you can play it directly.
Level 06 · Your move
The code will
not crack itself.
Jump into a match, deduce faster than the table, and climb the leaderboard.