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 Very Easy to Master, 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
• Works offline — after the first visit, play without an internet connection
• Mobile-friendly — responsive design that works on screens from 320px to large desktops

How It Works

Sudoku69 runs entirely in your browser. Your game progress and theme settings are saved in your browser’s local storage, so nothing is ever sent to a server. Your data stays on your device.

Puzzles are generated on-the-fly with a built-in solver that guarantees every puzzle has exactly one valid solution. Each difficulty level controls how many cells are revealed at the start.

Technology

Built with modern web standards using Astro, 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.