About Sudoku Games
Sudoku Games is a small, independently built website with one purpose: a Sudoku board that is pleasant to use, loads instantly, and does not ask you for anything.
Why it exists
Most free Sudoku sites work, technically. They are also slow, buried under interstitials, and increasingly want an account before they will let you play. This one was built because a puzzle that takes ten minutes should not need a twenty-second loading screen and a sign-up form in front of it.
There is no registration here, no email capture, and no paid tier. Advertising covers the hosting bill, and the ads are kept out of the board area.
How the puzzles are made
Every puzzle is generated on your own device, at the moment you ask for it, rather than pulled from a fixed library. The generator fills a complete valid grid, then removes clues one at a time — checking after each removal that the puzzle still has exactly one solution. A puzzle that would become ambiguous keeps its clue.
This matters more than it sounds. Grids with multiple valid solutions are common on the open internet, and they are maddening to play: you follow the logic correctly and still get marked wrong. Uniqueness is verified here before you ever see the board, which is also what lets us promise that no puzzle ever requires guessing. It is the same check the Sudoku solver runs on a grid you enter from somewhere else, which is how it can report that a puzzle has two answers rather than one.
Difficulty is set by how many clues are removed and how far the solver has to reach. Because generation happens locally, the same difficulty produces a genuinely different puzzle every time — there is no pool to exhaust.
Design notes
The interface is built around a few decisions worth stating plainly:
- Peers are shaded. Selecting a square highlights its row, column and box, because scanning is the core activity and the interface should assist it rather than make you track it in your head.
- Mistakes are flagged immediately. Three of them end the game. This is a constraint, not a punishment — it rewards placing a digit only when you can say why.
- Monospaced digits. Numbers sit on a fixed grid the way they would on graph paper, so the board does not shimmer as you fill it.
- No web fonts. System fonts only, so the first paint is immediate on a slow connection.
- Full keyboard support. Arrow keys move, digits place, N toggles notes, P pauses, Backspace erases.
The leaderboard
The daily and weekly boards exist because a solve is more satisfying when it counts for something, but requiring an account for that would undo the whole point of the site. So they take a nickname and nothing else. Boards run on UTC days and weeks so everyone competes on the same one, and old entries expire on their own.
Get in touch
Bug reports, a puzzle that looks wrong, an accessibility problem, or just a suggestion — all welcome at contact@sudokugames.online, or through the contact page. Reports about a specific puzzle are especially useful; include the difficulty and roughly what you were seeing.