Privacy Policy

Last updated: July 24, 2026

Information we handle

We may process the email address and nickname provided at registration, authentication data, challenge progress and submissions, and operational logs required to secure and troubleshoot the service. Passwords are not intended to be stored in plain text.

Purposes

• Authentication and account management.
• Saving and displaying learning progress.
• Preventing misuse and investigating failures.
• Improving service reliability and educational content.

Anonymous performance metrics

Public pages may send LCP, INP, CLS, and TTFB measurements. The payload excludes the page URL, account ID, cookies, IP address, and user agent. An IP address is used transiently only to enforce request-rate limits and is not stored with a metric.

Cookies

Cookies support sign-in, CSRF protection, and session management. Disabling them may prevent authenticated features from working.

Retention and requests

Information is kept only as needed for its purpose and applicable obligations. Use the contact page for access, correction, deletion, or privacy questions.