Privacy Policy

Last updated: November 12, 2024

Overview

chess.koz.tv provides free chess game analysis powered by Stockfish engine. This Privacy Policy explains how we collect, use, and protect your information when you use our website and Chrome extension.

Information We Collect

Chess.com Game Data

When you use our Chrome extension or manually import games, we collect:

  • Chess.com username (public)
  • Game PGN (Portable Game Notation)
  • Game metadata (date, time control, result, player ratings)
  • Opening information and move sequences

Important: We only access publicly available game data from Chess.com. We do not collect any private or personal information beyond your public Chess.com username.

Analysis Data

When you analyze games, we store:

  • Stockfish engine evaluations for each position
  • Move classifications (best, excellent, good, inaccuracy, mistake, blunder)
  • Accuracy scores calculated using the Lichess formula
  • Opening detection results with ECO codes

Technical Data

We automatically collect standard web server logs including:

  • IP address
  • Browser type and version
  • Device information
  • Access times and referring URLs

How We Use Your Information

We use the collected information to:

  • Provide chess game analysis and insights
  • Store your game history and analysis results
  • Identify patterns and weaknesses in your gameplay
  • Generate aggregate statistics and recommendations
  • Improve our service and fix technical issues
  • Prevent abuse and ensure service stability

Chrome Extension Permissions

Our Chrome extension requires the following permissions:

activeTab

Used to detect when a game ends on Chess.com and inject the "Analyze on chess.koz.tv" button.

storage

Used to save user preferences such as development mode settings. No personal data is stored locally.

host_permissions

https://www.chess.com/* - To detect game completion and extract game IDs
https://chess.koz.tv/* - To communicate with our analysis service

Data Storage and Security

Your game data and analysis results are stored in our secure PostgreSQL database. We implement industry-standard security measures including:

  • Encrypted connections (HTTPS/TLS)
  • Regular security updates and patches
  • Access controls and authentication
  • Regular backups

Third-Party Services

We interact with the following third-party services:

Chess.com API

We fetch publicly available game data from Chess.com's public API. Please refer to Chess.com's Privacy Policy.

Stockfish Engine

We use the open-source Stockfish chess engine running on our servers for analysis. No data is shared with external parties.

Data Retention

We retain your game data and analysis results indefinitely to provide you with historical insights and track your progress over time. You can request deletion of your data at any time by contacting us.

Your GDPR Rights

Under the General Data Protection Regulation (GDPR), you have the following rights:

Right to Access (Article 15)

You can view all your data at any time by visiting your dashboard.

Right to Data Portability (Article 20)

Export all your data in JSON format:

Settings → Export My Data

Right to Erasure / Right to be Forgotten (Article 17)

Not applicable - We only store publicly available information:

  • Chess.com usernames (public)
  • Public games from Chess.com API
  • Stockfish analysis of public games

Under GDPR Article 17(3)(e), the right to erasure does not apply when processing is necessary for archiving purposes in the public interest or scientific research. Additionally, publicly available information is not considered "personal data" under GDPR when it's already accessible through other public sources (Chess.com).

Right to Rectification (Article 16)

If you find inaccurate data, please contact us at privacy@chess.koz.tv

Right to Object (Article 21)

You can object to analytics tracking:

Settings → Cookie Preferences → Change preferences

Right to Withdraw Consent (Article 7)

You can withdraw your cookie consent at any time from the Settings page.

To exercise any of these rights, visit your Settings page or contact us at privacy@chess.koz.tv.

Children's Privacy

Our service is not directed to children under 13. We do not knowingly collect personal information from children under 13. If you believe we have collected information from a child under 13, please contact us immediately.

Cookies and Tracking

We use cookies to improve your experience. When you first visit our site, you will see a cookie consent banner where you can choose to accept only essential cookies or all cookies.

Essential Cookies

These cookies are necessary for the website to function and cannot be disabled. They include cookies for remembering your cookie preferences.

Analytics Cookies (Optional)

Only loaded if you consent to analytics cookies:

  • Google Analytics: Helps us understand how visitors use our site
  • Yandex Metrika: Provides additional analytics insights

You can change your cookie preferences at any time from the Settings page. We do not use cookies for advertising or marketing purposes.

Changes to This Policy

We may update this Privacy Policy from time to time. We will notify you of any significant changes by updating the "Last updated" date at the top of this page.

Contact Us

If you have any questions about this Privacy Policy or our data practices, please contact us:

Open Source

chess.koz.tv is an open-source project. You can review our code and privacy practices on our GitHub repository.

This Privacy Policy is effective as of the date stated at the top of this page.