Privacy Policy

Cantong has no accounts. Most of what you do here never leaves your browser, and the little that does is listed below.

1. Information we store

Stored on our servers

  • Leaderboard entries: nickname, score, game and time, saved only when you press "Submit" and shown publicly on the board. Please do not use a real name or contact details as a nickname.
  • Daily puzzle records (Sudoku, Minesweeper and other puzzles that change every day): nickname, number of tries and time, together with a random device ID used to prevent duplicate entries from the same browser. The ID is a random string your browser creates and stores; it does not identify you or your device.
  • Would You Rather votes: an anonymous count per question and side. Nothing is attached to your vote.
  • Short share links: when you press "Share", the result parameters (app path and result values) are stored so the link can be shortened. They contain exactly what the result card shows, nothing more.
  • Per-app view counts: how many times each app was opened per day, as a total only. Who opened it is not stored. This drives the "Popular" ordering on the home page.
  • IP address: used only for rate limiting (five submissions per minute) on leaderboards, puzzles and short links, and deleted automatically after 7 days.

Kept only in your browser (never sent to us)

  • Personal bests, the last nickname you typed, favorites, theme and sidebar settings, flashcard progress and the random device ID above.
  • Tool preferences such as the last output format you chose.
  • All of this lives in your browser's localStorage and disappears when you clear site data.

What a share link contains

A link made with the "Share" button carries the result values (score, test outcome, calculator result) in its address. Anyone you send it to can see those values, and the same values are stored on our side as described under short share links above, so choose recipients accordingly.

2. Information collected automatically

  • Hosting (Cloudflare): access logs (IP address, time, browser information) may be processed by Cloudflare's infrastructure for operation and security. Cloudflare privacy policy
  • Visit statistics (Cloudflare Web Analytics): a cookie-free script counts page views. It does not identify individuals; we see aggregates such as browser type, country and page path.
  • Fonts and libraries (jsDelivr CDN): your IP address is sent to the CDN when fonts or libraries are loaded. jsDelivr privacy policy
  • Image, PDF, HEIC, blur, pixel art, EXIF and QR tools: all processing happens inside your browser. No file, original or result, is sent to Cantong or anywhere else.
  • Face reading, symmetry, animal lookalike, personal color and palm reading: the photo is analyzed on your device with a recognition model your browser downloads. The photo is never uploaded, and a share link carries only the analysis values, not the image.
  • What Is My IP: displays the IP, country and network information that Cloudflare attaches to your connection. Cantong does not store it.

3. Ads and cookies

Cantong shows Google AdSense ads to cover its running costs. Google and other third-party vendors use cookies (including the DART cookie) and advertising identifiers to serve ads based on your visits to this and other websites.

  • You can opt out of personalized ads from Google in Google Ads Settings, and from other vendors at aboutads.info.
  • How Google uses data from partner sites: Google partner sites policy
  • Where the law requires prior consent (for example in the EU and the UK), you will be asked before personalized-ad cookies are set.
  • You can block cookies in your browser; Cantong's games and tools keep working without them.

Cantong itself sets no login cookies and counts visits without cookies. The only first-party cookie is lang, which remembers the language edition you chose on your first visit.

4. Retention

  • Leaderboard and puzzle records (nickname, score): kept while the service operates. Ask us if you want yours removed.
  • Result values behind short links: kept while the service operates so the links keep working. Send us the link if you want it removed.
  • IP addresses: deleted 7 days after submission.
  • Per-app view totals: not personal data; kept for statistics.
  • Browser-side data: until you delete it.

5. Sharing with third parties

Apart from the processing by the infrastructure providers named above (Cloudflare, Google AdSense, jsDelivr), no information is shared with or sold to anyone.

6. Children

Cantong is not directed at children under 13 and knowingly collects no personal information from anyone. If a child uses a leaderboard, please make sure the nickname does not identify them.

7. Your rights

To have a leaderboard or puzzle entry or a short link removed, send the nickname (or the link), the game and the approximate time it was posted to the address below. It will be deleted without delay once confirmed.

Contact: [email protected] ยท contact page

8. Changes

Changes to this policy are posted on this page with a new effective date.

Effective: 2026-09-03