Privacy

Internet Sudoku is designed to work without accounts. Puzzle progress preferences, and daily streaks are saved locally in your browser so you can continue where you left off.

Local storage

The app uses localStorage to save puzzle entries, notes, mistake count, timer progress, hints used, pause state, selected cell, daily completion streaks, and simple game settings such as highlighting and note cleanup. Undo history is kept only in memory for the active session and is not written to localStorage. This information stays on your device and is not tied to a login.

Cookies and accounts

Internet Sudoku does not require an account and does not use cookies for game state. Clearing this site’s browser data removes saved puzzles and settings.

Sharing links

The copy link button only copies the canonical puzzle URL for the visible daily puzzle. It does not include your progress, notes, or settings.

Analytics

Internet Sudoku uses Vercel Analytics to understand broad site usage. Analytics is not used to collect puzzle entries, notes, mistakes, timer progress, streaks, or saved game state.