Why SudoKoum exists

The name SudoKoum is a joke that stuck and a tribute to Koum, Alexis Leroy's wife and his biggest Sudoku fan. She was tired of having to print grids to play with family and friends. Ads in apps annoyed her just as much.

SudoKoum answers both of those frustrations.

Alexis Leroy wanted the same grid for the whole table, challenges between friends and family, leaderboards and statistics, with no ads and no subscription. Many sudoku apps live off advertising or a monthly subscription. So he built the app he wanted. Here is what it promises.

1. Sudoku is better with other people

Sudoku has a reputation as a solitary game. For two years, Alexis Leroy saw the opposite. People close to him played Sudoku with family or friends by printing grids. That picture is what made him want to build SudoKoum.

They deserved better than the printer. Same grid. Who will be the best? A challenge sent as a link, the same grid for everyone, each player plays whenever they want, and the leaderboard does the rest. No scheduling, no pressure, just the pleasure of measuring up against the people you love, family and friends alike.

2. Winning has to mean something

A leaderboard only has value if the rules are the same for everyone. In SudoKoum, every mistake costs points and, in a challenge, the third mistake loses the game. A hint reveals a cell that earns no points, with three hints at most per game. The score is calculated the same way for every player.

It is more demanding, and that is the point. When you beat your sister by one point on an Expert grid, that point is real.

3. Your attention is not for sale

Sudoku is time for yourself. Ten minutes of mental silence in a noisy day. Ad-funded apps live off the opposite, since every interruption is their revenue. The more they interrupt, the more they earn.

SudoKoum contains no advertising. Not while you try it, not in Premium, not "for now". Never. This page exists so that promise cannot be quietly walked back.

4. You buy a game once

A monthly subscription for placing digits in boxes is a no.

SudoKoum costs €3.99, once. You try it first, friend challenges included, and if you get hooked, a single purchase takes you Premium for life. That one-time price is meant to cover what it cost to make the app, with nothing else to pay afterwards.

Who makes SudoKoum

SudoKoum is made by Alexis Leroy, a developer from France, under the name Kaizen Suru. No growth team, no dark patterns to push you into paying. The app only counts anonymous totals, screens opened and buttons tapped, to learn what helps and what gets in the way. Nothing in them points to a player, and a switch in the settings turns them off.

The app is translated into 13 languages and works offline in solo mode. Link it to your Apple or Google account and your level, stats and achievements follow you from one phone to the next. The Premium purchase stays tied to your App Store or Google Play account, and the "Restore purchase" button gives it back to you on a new device. The kind of details that take time to build and are only noticed when they are missing.

SudoKoum is coming to the App Store and Google Play. Leave your email to be notified at launch, or see how SudoKoum compares to the other apps.

Page updated on October 16, 2026. Questions? The FAQ covers the most common ones.