About Sudoku69

Sudoku69 is a free, ad-free online Sudoku puzzle game. Play classic 9x9 Sudoku directly in your browser with no downloads, no accounts, and no advertisements.

Features

Six difficulty levels — from Easy to Legendary, suitable for beginners and experts alike
Pencil marks — track candidate digits with notes mode for advanced solving
Undo — step back through your moves at any time
Three themes — light, dark, and sepia color schemes to match your preference
Keeps going through hiccups — a small local stash of puzzles covers short outages of our puzzle server
Mobile-friendly — responsive design that works on screens from 320px to large desktops

How It Works

The game runs in your browser. Your progress and theme settings are saved in your browser's local storage and stay on your device; only the puzzles themselves are fetched from our puzzle server, and a small local stash keeps you playing through short outages.

Every puzzle is generated, verified and rated by us before it reaches the site: each one has exactly one valid solution and a difficulty rating that places it in its level. Our puzzles are our copyrighted work — see the Puzzle License for what you may and may not do with them.

Technology

Built with modern web standards using Next.js, React, TypeScript, and Mantine. Sudoku69 works on any device with a modern browser, whether it is a desktop computer, tablet, or phone. No app download is needed.

Contact

Found a bug or have feedback? Reach us at contact@sudoku69.com.