Privacy and data

Version dated September 21, 2026

Guest practice

Five problems can be solved without an account. Guest answers exist only while the page is open and do not become a personal history. We record aggregate start and answer events with the selected grade and no user identifier.

Adult account

An adult provides an email address, username, display name, and password. The email address is confirmed through a one-time link. We store the confirmation date and the version of the accepted terms. The password is stored as a salted hash.

Child profile and consent

After confirming their email, an adult can create a child profile. We use only a nickname, grade, separate username, password, practice results, awards, and settings. A full name, date of birth, school, address, and telephone number are not required. Before creating the profile, the adult confirms that they are the child’s parent or legal guardian and permits the processing of this limited data. We store the version of the consent text and the time of consent.

Sessions, security, and analytics

After sign-in, the site uses a secure session cookie for up to 30 days. To limit repeated sign-in attempts, the site stores a keyed fingerprint of the network address, the time, and the number of attempts; the original address is not stored in this table. The site runs on Cloudflare, and Cloudflare Web Analytics measures visits and page speed. Cloudflare processes technical request data. Resend sends messages from the project’s mail subdomain for email confirmation, account recovery, and data deletion. Messages sent to hello@mozgoquest.com are forwarded to Yandex Mail.

Access and deletion

From the adult dashboard, an adult can download a JSON copy of their family data. Deletion requires the password, a message to the confirmed email address, and a separate final confirmation. The adult account, linked child profiles, sessions, and learning data are deleted. Only a de-identified deletion event remains in the log. Working backups expire within 30 days.

A short privacy explanation for children is also available. Contact hello@mozgoquest.com with questions about this notice or the data we hold.