What we collect
- Chess.com and/or Lichess username
- Email address (optional)
- Country and nationality flag — from Chess.com/Lichess profile or detected from IP via Vercel
- Player ratings (Elo) from Chess.com/Lichess at connection
- Chess game history from Chess.com and Lichess public APIs — moves, results, opponent usernames, dates, engine evaluations
- Device type, browser, OS, referring website (via Vercel Analytics)
- Puzzle attempt data: moves played, solve times, correct/incorrect results
- Streak and accuracy statistics
- Referral codes and referral relationships
- Payment status via Stripe — we never see card details
- Session cookies for authentication
We collect personal data linked to your chess account identity. This data is used exclusively to provide your personalised puzzle training experience. We do not sell your data to third parties. You can request complete deletion at any time.
Third-party services
- Google Analytics GA4 — page views and behaviour tracking
- Google Search Console — monitors how cassandrachess.com appears in Google search results. No personal user data is collected.
- Bing Webmaster Tools — monitors how cassandrachess.com appears in Bing search results. No personal user data is collected.
- Google AdSense — advertising cookies for free users. Paid users are exempt.
- Meta Pixel — ad performance tracking. We share hashed email and country with Meta for audience matching.
- Microsoft Clarity — session recordings and heatmaps to understand how users interact with the site. Clarity may collect IP address, device and browser info, and user interactions. Only loaded with cookie consent.
- Microsoft Advertising UET — conversion tracking for Bing Ads campaigns. Collects page views and interaction data. Only loaded with cookie consent.
- Vercel — hosts the application and provides analytics including page views, device type, browser, operating system, country, and referring website. This data is pseudonymous and not linked to individual user accounts. Vercel also processes inbound emails sent to josh@cassandrachess.com.
- Vercel Speed Insights — collects Core Web Vitals and performance metrics including page load times, device type, and browser. This data is pseudonymous and not linked to individual user accounts.
- Supabase — database hosted in United States
- Resend — email delivery
- Stripe — payment processing
- Chess.com public API — game history, rating, nationality flag
- Lichess public API — game history, rating, nationality flag
- Stockfish WASM — runs entirely in your browser, no data sent externally
Your rights
Request deletion by emailing josh@cassandrachess.com. Unsubscribe from emails anytime. EU/UK users have full GDPR rights.
Cookies
Session (login), preference (language/banners), analytics (GA4/Vercel), advertising (AdSense/Meta Pixel — free users only).
What happens if you decline cookies
If you decline cookies: Google AdSense will not load and you will not see personalised ads. Meta Pixel will not load and your visit will not be tracked for advertising purposes. Google Analytics will run in anonymous mode only — no personal identifiers are collected. Session cookies required for login are always active regardless of your choice as they are essential for the service to function. You can change your cookie preferences at any time using the Cookie Preferences link in the footer.