Terms of Service

Last updated: June 2026

1. Acceptance of Terms

By accessing or using ChessMeris ("the Service"), you agree to be bound by these Terms of Service. If you do not agree, please do not use the Service.

2. Description of Service

ChessMeris is a free online platform for chess puzzle training. It offers puzzle modes, ELO tracking, streaks, achievements, and social features. All features are currently free of charge during the launch period.

3. User Accounts

You may use the Service as a guest (limited access) or by creating an account with a valid email address. You are responsible for maintaining the confidentiality of your account credentials and for all activities that occur under your account.

You must not create accounts for other people without their permission, use the Service for any unlawful purpose, or attempt to disrupt the Service.

4. User Content

You may provide a display name, country, and avatar as part of your profile. You agree not to use offensive, impersonating, or misleading display names. We reserve the right to remove any content that violates these terms.

5. Intellectual Property

The puzzle database used by ChessMeris is sourced from Lichess.org under the Creative Commons CC0 license. The ChessMeris platform, design, and code are the property of the Service operator. You may not copy, modify, or redistribute them without permission.

6. Disclaimer of Warranties

The Service is provided "as is" without warranties of any kind. We do not guarantee uninterrupted access, error-free operation, or permanent data retention. We reserve the right to modify or discontinue the Service at any time.

7. Limitation of Liability

To the fullest extent permitted by law, ChessMeris and its operator shall not be liable for any indirect, incidental, or consequential damages arising from your use of the Service.

8. Changes to Terms

We may update these Terms at any time. Continued use of the Service after changes constitutes acceptance of the new Terms. We will notify users of significant changes via email when possible.

9. Contact

For any questions regarding these Terms, please contact us at contact@chessmeris.com.

Privacy Policy

Last updated: June 2026

1. Data Controller

The data controller responsible for your personal data is:

2. Data We Collect

When you create an account and use ChessMeris, we collect the following data:

• Account data: email address, hashed password
• Profile data: display name, country, avatar selection
• Game data: ELO ratings, puzzles solved, streaks, achievements, theme statistics, sprint and survival scores
• Social data: friend relationships and requests
• Technical data: IP address (via Supabase and Vercel infrastructure), browser type, device type (via Google Analytics)

Guest users do not create an account and no personal data is stored beyond the current session.

3. How We Use Your Data

• To provide and operate the Service (account management, game progress tracking)
• To display your profile and statistics to friends you have accepted
• To send streak reminder emails if you have an active streak at risk (you may opt out in Settings)
• To send weekly progress summaries (optional, opt-out available)
• To analyse usage and improve the Service via aggregated analytics

4. Legal Basis (GDPR)

• Contract performance: processing necessary to provide the Service you signed up for
• Legitimate interest: analytics and service improvement
• Consent: optional emails (streak reminders, weekly summary)

5. Data Retention

Your data is retained as long as your account is active. If you delete your account, all personal data is permanently deleted within 30 days. Anonymised aggregate statistics may be retained indefinitely.

6. Third-Party Services

We use the following third-party services that may process your data:

• Supabase (supabase.com) — database and authentication. Data stored in EU region. Privacy policy
• Vercel (vercel.com) — hosting and infrastructure. Privacy policy
• Google Analytics (google.com) — anonymous usage analytics. Privacy policy
• Resend (resend.com) — transactional email delivery. Privacy policy

7. Your Rights (GDPR)

As a user based in the European Economic Area, you have the following rights:

• Right of access: request a copy of your personal data
• Right to rectification: correct inaccurate data via your profile settings
• Right to erasure: delete your account and all associated data via Settings → Delete account
• Right to data portability: request an export of your data
• Right to object: opt out of analytics or email communications

To exercise any of these rights, contact us at contact@chessmeris.com.

8. Cookies

ChessMeris uses localStorage and sessionStorage to maintain your session and preferences. Google Analytics sets cookies for usage tracking. No advertising cookies are used.

9. Data Security

We implement industry-standard security measures including encrypted connections (HTTPS), hashed passwords, and row-level security on our database. However, no system is completely secure and we cannot guarantee absolute security.

10. Contact & Complaints

For any privacy-related questions or to exercise your rights, contact: contact@chessmeris.com

You also have the right to lodge a complaint with your national data protection authority (in France: CNIL).