Privacy

What this site stores

There’s no sign-in during a test run, and we don’t ask for your email or contact details when you play. For publisher questions, see the contact page.

• Anonymous session ID
• Each test’s target card, your pick, and correctness
• Whether feedback was shown after that pick
• Derived session metrics and aggregate meta stats
• Your browser’s user agent string on the session row (for coarse device and browser diagnostics)
• Optional two-letter country code (e.g. US) on the session row when you start a session. We do not ask for device GPS or browser location permission. Your browser may request this site’s Cloudflare /cdn-cgi/trace endpoint (built in to Cloudflare hosting; not custom server code we run) or, if that fails, geojs.io for a coarse country from IP. Only the country code is saved in our database—not your IP address. If lookup fails, nothing location-related is stored. When available, this two-letter code is shown on the public leaderboard next to that session’s score
• A random resume secret on the session row (not exposed in the public results view) so a private “save for later” URL can authorize additional test blocks

Public vs private links

The app offers two kinds of links after a run. A public link (under /results/…) only shows aggregate scores for that session. A private “save for later” link (under /later/…) includes a secret token: anyone who has that full URL can append more blocks of ten tests to the same session, and metrics are recomputed over every logged pick. Treat the private link like a password.

If you paste a private link into another site or app, referrers or logs there could expose it—copy it only through channels you trust.

Analytics

This site may use Google Analytics 4 (via Google’s hosted gtag.js on googletagmanager.com) to understand aggregate traffic and navigation. It is enabled only when the site operator sets a measurement ID at build time.

Ads and consent

This site uses Google AdSense. Depending on your location, consent prompts may be shown for personalized ads and measurement.

When you open your full session report, a Google AdSense display placement may load on that page. Use Google’s close or ad choices where shown. Depending on your location, consent prompts may apply before personalized ads or measurement.

For Google’s separate rewarded ad experience on the web, publishers enable AdSense Offerwall in the account (not a slot ID in this repo). See policies for rewarded ads (rewards must follow Google’s rules; skipping a rewarded placement must not block ordinary use of the site).

Google may use cookies and similar technologies for ads and measurement. See How Google uses data in advertising, How Google uses cookies, and manage personalized ads at Google Ad Settings.