Privacy Policy

Lucid Chess LLC  ·  Last updated: April 17, 2026

This Privacy Policy describes how Lucid Chess LLC ("we", "us", or "the app") collects, uses, and protects your information when you use the Lucid Chess mobile application and any associated web surfaces. This policy applies to the TestFlight beta and all production releases unless superseded by a subsequent version.

If you do not agree with this policy, please do not use the app.

1. Information We Collect

1.1 Account Information

When you create an account we collect:

• Email address
• Username (chosen by you)
• Password (stored as a one-way cryptographic hash — we never see or store your actual password)
• Optional: self-reported chess rating (for internal calibration analysis only; never shown to other users)

1.2 Gameplay and Progression Data

To provide the core product experience we collect and store:

• Puzzle attempt history (which puzzles you attempted, your answers, outcomes)
• Blind Rating (BR) and Puzzle Rating (PR) history over time
• Training mode usage (Daily Path, Blind Tactics, Double Blind, Play vs Bots)
• Ladder progression and ceremony milestones
• Hints and assists used during attempts
• Achievements earned
• Bots defeated and ply-survival statistics
• In-app economy balances (Keys and Lucidity)
• Store purchases and content library

1.3 Analytics

We use Google Firebase Analytics to understand how the app is used in aggregate. Events we log include:

• Session start and session end
• Onboarding completion
• Training mode entries and outcomes
• Paywall impressions
• Subscription events and store purchases
• Crash reports and errors (via Firebase Crashlytics)

Analytics events are associated with your account so that we can compute retention cohorts, identify friction points in onboarding, and measure feature usage. We do not sell analytics data to third parties.

1.4 Payment Information

Payment processing is handled by Apple (App Store), RevenueCat, and Stripe (for web subscriptions). We do not collect or store your payment card details. We receive subscription status, purchase records, and platform-specific transaction identifiers so that we can:

• Grant you the content and features you purchased
• Process refunds when required
• Restore your purchases across devices

1.5 Device and Technical Information

We automatically collect basic technical information such as:

• Device type and operating system version
• App version
• Anonymous device identifiers provided by the platform
• IP address (at time of API requests; used for rate limiting and security; not stored long-term)

1.6 Chess Engine Requests

When you play against higher-tier bots, the app sends chess positions (FEN strings) and engine parameters to our Stockfish sidecar service for move computation. These requests do not contain personal information and are not logged against your account.

2. How We Use Your Information

We use the information described above to:

• Provide, maintain, and improve the app
• Personalize content and difficulty based on your rating and progression
• Compute and display ratings, achievements, and ceremonies
• Process subscriptions and in-app purchases
• Communicate important service updates (e.g., subscription lifecycle, security notices)
• Prevent fraud, abuse, and unauthorized access
• Comply with legal obligations

We do not sell your personal data to third parties.

3. Third-Party Services

Lucid Chess relies on the following third-party services. Each operates under its own privacy policy:

Service	Purpose	Provider
Firebase Analytics	Usage analytics	Google LLC
Firebase Crashlytics	Crash reporting	Google LLC
Supabase	Account, progress, and leaderboard storage	Supabase Inc.
RevenueCat	Subscription and purchase management	RevenueCat, Inc.
Apple App Store	iOS payment processing	Apple Inc.
Stripe	Web payment processing	Stripe, Inc.
Fly.io	Chess engine server hosting	Fly.io, Inc.

4. Data Storage and Retention

• Account data and progression data are stored on our servers (Supabase) for as long as you maintain an active account.
• Local gameplay data is stored on your device in an encrypted local database (Drift / SQLite). This data does not leave your device unless it is synchronized to your account.
• Analytics data is retained by Firebase Analytics according to the retention window configured for the project (default: 14 months for event data).
• Crash reports are retained by Firebase Crashlytics for up to 90 days.
• Payment records are retained as long as required by applicable tax and consumer-protection law.

5. Your Rights

You have the right to:

• Access — request a copy of the personal data we hold about you
• Correct — request corrections to inaccurate data
• Delete — request deletion of your account and associated data. Subscription records retained for legal or tax purposes may survive account deletion.
• Export — request your gameplay history in a portable format
• Withdraw consent — opt out of non-essential analytics (contact us to request)

To exercise any of these rights, email us at the address in Section 10.

If you are located in the European Economic Area, the United Kingdom, or California, you may have additional rights under GDPR, UK GDPR, or CCPA. We honor those rights regardless of your location.

6. Children's Privacy

Lucid Chess is not intended for users under the age of 13. We do not knowingly collect personal information from children under 13. If you believe a child under 13 has created an account, please contact us so we can delete it.

7. International Transfers

Your data may be processed in the United States or in other jurisdictions where our service providers operate. We take reasonable steps to ensure your data is handled consistently with this policy regardless of where it is processed.

8. Security

We use industry-standard security practices including encryption in transit (HTTPS/TLS), encryption at rest on our servers (via Supabase), hashed passwords, and least-privilege access controls. No system is perfectly secure — if you suspect your account has been compromised, contact us immediately and change your password.

9. Changes to This Policy

We may update this Privacy Policy from time to time. When we make material changes, we will update the "Last updated" date at the top and, for significant changes, notify you in-app or via the email associated with your account. Continued use of the app after an update constitutes acceptance of the revised policy.

10. Contact

Questions or requests related to this policy:

Email: [email protected]

For security disclosures, please include "Security" in the subject line.

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