Privacy

Last updated 2026-10-16.

• No accounts. Your progress, spaced repetition data and unlock code are stored in your browser's local storage on your device. We cannot see them.
• Analytics. We may use Cloudflare Web Analytics, which does not use cookies or track you across sites, to count page views. We may record anonymous events (diagnostic started/completed, checkout clicked, purchase completed) with the page and campaign tag, no personal data.
• Payments. Checkout is handled by our payment processor (for example Stripe). We receive your email and payment status from them to deliver your purchase and handle refunds; we never see your full card number.
• Campaign tags. If you arrive from a link with a campaign tag, we store that tag on your device and pass it to checkout so we know which links work.
• Contact. [email protected].