Privacy policy

Without an account (guest mode)

You can take quizzes without signing up. In that case everything stays in your browser (localStorage) and is not sent to the server:

• your best score for each topic and level (quiz:best:*);
• questions to review - the numbers of questions you got wrong, with the review step and the next review date (quiz:review:*);
• an unfinished quiz - the question order and your answers, if "Save quiz progress" is on (quiz:attempt:*), and that setting itself (quiz:resume-enabled);
• coding tasks - the list of solved tasks (task:solved) and your code for each task (task:draft:*); these stay in the browser only, even when you're signed in;
• your chosen theme (theme);
• the time you last sent the feedback form, to limit frequent submissions (feedback:lastSentAt).

To delete this data, clear the site data in your browser settings. Turning off "Save quiz progress" deletes unfinished quizzes immediately.

With an account

You can sign in with GitHub or Google. We only request your basic profile and get no access to your repositories, emails or any other data in those services. When you sign in we store:

• your GitHub or Google account id, email, name and avatar URL;
• your best scores per topic and level: correct answers, total questions and the update time. Guest scores are moved to your account on first sign-in and removed from the browser.
• questions to review: the numbers of questions you got wrong, per topic and level, with the review step and the next review date. The guest list is also moved to your account when you sign in.

The sign-in session is kept in your browser's localStorage (a key like sb-…-auth-token) and removed when you sign out. Your avatar loads directly from GitHub's or Google's servers. The "Sign in with Google" button loads from Google's servers only when you open the sign-in menu.

Unfinished quizzes stay in the browser only, even with an account.

Feedback

You can report bugs and share ideas without an account; it is voluntary. We store the message type (bug or idea), the text, an optional email for a reply, the interface language, the page address, the time it was sent and, when signed in, the link to your account. Only the site owner can read messages. Please don't include unnecessary personal data in the text.

When an account is deleted, the link to it is removed, and the messages themselves are kept until the owner deletes them.

Cookies

The site uses only technical cookies, no advertising or analytics ones:

• NEXT_LOCALE - your interface language, for 1 year;
• country - a country code (e.g. UA) to show a suitable way to support the project, for 1 day.

The sign-in session is not a cookie; it lives in localStorage (see "With an account").

Visit statistics

To understand which topics and languages people need and where they abandon a quiz, we use Vercel Web Analytics. It sets no cookies and does not store your IP address: visitors are told apart by a request hash that changes every day, so it cannot be used to identify you. It collects:

• the page you open and the site you came from;
• country, device type, browser and operating system;
• quiz events: start, reaching questions 10, 20, 30 and 40, the final percentage and how you shared a result.

This data is not linked to your account and is visible only to the site owner as aggregate statistics.

Supporting the project

The country is determined by the Vercel hosting from the request's IP address and stored only in the country cookie; we don't record your IP address or country.

Visitors from Ukraine see a link to a monobank jar, everyone else sees a Buy Me a Coffee button. That button loads a script from buymeacoffee.com, and Buy Me a Coffee's privacy policy applies to it. Payments happen on those services' websites; we never receive your card details.

Where data is stored

• website and visit statistics: Vercel. Technical request logs may contain your IP address;
• database and sign-in: Supabase (Ireland, EU);
• sign-in provider: GitHub or Google, whichever you choose.

Fonts are served from the site itself, without third-party services.

Deleting your data

To delete your account and all scores linked to it, email kutsenko.alexander@gmail.com from the address linked to your account. Guest data is deleted by clearing the site data in your browser.

Contact

Questions about your data: kutsenko.alexander@gmail.com.