Privacy Policy

99chess (“we”, “us”) is a chess training service at 99chess.com. This policy explains what data we collect, why we collect it and what your choices are. The short version: we collect what the product needs to work, we do not sell your data, and you can ask us to delete your account at any time.

What we collect

• Account data: your e-mail address, nickname, a hashed password (never the password itself), your interface language, and — if you sign in with Google — the identifier Google provides for your account.
• Chess activity: games you play or import, puzzle attempts, training progress, opening study results and the analysis our engine produces for them.
• Linked platforms: if you link a chess.com or lichess username, we fetch your public game archives from those platforms. We never receive your passwords for them.
• Telegram: if you link Telegram for reminders, we store your chat identifier and language.
• Technical data: product analytics events (pages visited, features used), approximate location derived from your IP, browser and device type.

How we use it

• To run the product: reviews of your games, puzzles built from your mistakes, your training program and progress.
• To improve the product: we analyse anonymised usage patterns in PostHog, hosted in the European Union.
• To measure advertising: we use the Google Ads tag and the Reddit pixel to know that a registration came from an ad. These tools set their own cookies; see their policies for details.
• To analyse games with AI: positions and moves from your games are sent to AI providers (such as OpenAI) to generate coaching text. Your identity is not attached to those requests.
• To e-mail you: account verification and occasional product announcements, sent via Resend. Every non-essential e-mail tells you how to opt out, and you can always opt out by contacting us.

Cookies and local storage

We use browser local storage for your preferences (language, board settings, drafts of your progress) and cookies set by the analytics and advertising tools listed above. Blocking those cookies does not break the product.

Sharing

We do not sell personal data. We share it only with the service providers that run the product for us — hosting, e-mail delivery (Resend), analytics (PostHog), AI analysis providers, and ad platforms for conversion measurement — each receiving only what its job requires.

Retention and deletion

We keep your data while your account exists. Write to us and we will delete your account and the personal data attached to it. Aggregated statistics that no longer identify you may be kept.

Your rights

You can request a copy of your data, correct it, or have it deleted. If you are in a jurisdiction with specific privacy rights (such as the GDPR), we honour those rights on request.

Children

99chess is not directed at children under 13. If you believe a child under 13 has created an account, contact us and we will remove it.

Changes

If this policy changes materially, we will update this page and the date above.

Contact

support@99chess.com