Your data
Privacy & local storage.
What stays in your browser, what a page request sends to our infrastructure, and how to control optional measurement.
A game without an account
Sudoku Slate does not require a name, email address or account to play. Entered clues, notes and saved games are not uploaded to a game database. Your browser performs gameplay and puzzle-checking calculations.
This does not make a visit anonymous to network infrastructure. Loading a page requires a request to the hosting provider, as explained below. A puzzle included in a page URL is also part of that request.
What stays in this browser
| Data | Purpose and retention |
|---|---|
| Saved puzzles | Puzzle identity, your entries and notes, selected cell, elapsed time, mistakes, hints used, pause and completion state, and up to 80 undo steps. These let you resume in the same browser. There is no automatic expiry for saved games. |
| Completion history | Up to 730 first-completion records, containing puzzle ID, difficulty, daily date when applicable, completion time, elapsed time, mistakes and hints. Newer records replace older ones after this limit. |
| Recovery copies | If two tabs try to save the same puzzle, a separate copy keeps the conflicting entries and the time that copy was saved. Repeated conflicts in the same tab update its copy for that puzzle. These copies do not expire automatically; use Delete recovery copies below that puzzle to remove them without deleting the main saved game. |
| Preferences and current puzzle | Theme choice, puzzle sequence and the active puzzle for each game mode. An earlier saved-game entry may remain locally after migration so the original record is preserved. |
| Privacy choice | Your optional analytics choice is stored locally so the site can respect it on later visits. You can change the choice below. |
These records use browser site storage. They remain on this device until you or your browser remove them, except for the completion-history limit above. Private browsing, blocked storage, low disk space or browser cleanup may prevent saving or remove existing data. There is no server backup or cross-device sync.
Saving also needs browser support for coordinating writes across open tabs. If another tab has saved a newer version, the game pauses automatic saving and lets you choose which progress to use. If it cannot save safely, it tells you and you can keep playing without a saved copy. Time is saved periodically; abruptly closing or terminating a page can lose the most recent few seconds of elapsed time.
The solver keeps typed or pasted clues in the open page’s memory and passes them to a local Web Worker. It does not send those clues to a remote solving service or save the standalone solver input as a game archive. Clipboard access is used only when you select a copy control.
Hosting and essential request information
The website is hosted on Cloudflare. Delivering and protecting the site involves processing technical request information, such as the requested address, network address and request timing. Hosting and diagnostic logs may retain request metadata to operate the site and investigate failures or abuse.
Cloudflare describes its handling of service and end-user information in its privacy policy. Declining optional analytics does not prevent the requests needed to load and operate the website.
Optional analytics
Optional Google Analytics is off by default. If analytics is configured for this version of the site, the Google script loads only after you choose to allow it. Without that configuration, the site does not send analytics events to Google, even if a preference is saved.
When enabled with your consent, measurement helps identify useful pages and features through page views and actions such as starting or completing a game, requesting a hint, checking a puzzle or opening a print dialog. Event details can include a public puzzle ID, a random reference for one play, difficulty, outcome, duration and counts. The play reference links a start to its finish; it is not an account or cross-device identifier. Puzzle contents and candidate notes are not included in these events.
Google may process device and browser information and use cookies when its service is active. See how Google uses information from partner sites. Changing your choice stops future optional collection by this site; it does not erase information already sent to a provider.
Advertising and external links
This site does not currently display AdSense ads.
Links to other websites take you to services with their own privacy practices. The site does not control those services. If you choose to send an email, your email provider and the recipient process the message and any details you include.
Delete data or change a choice
- To remove only the local completion list, use Clear completion history on the daily page. This does not remove saved games.
- To remove saved games, notes, preferences and local completion records, open your browser’s privacy or site-data settings, find this website and delete its stored data. Close open game tabs first so they do not save the current game again.
- Use Analytics preferences above to allow or decline optional analytics. Clearing all site data also removes the stored preference; optional analytics starts off again until you make a new choice.
Cleared local progress cannot be restored by the website. Removing local site data does not delete hosting logs or information previously received by an external provider.
For privacy questions about this website, contact contact@sudokuslate.com. Include only the information needed to describe your question.