Terms of Service
Last updated: March 26, 2026
1. Service Description
Centipawn ("the Service") is a chess improvement tool that analyzes chess games using Stockfish and provides AI-generated explanations. The Service is operated from Norway.
2. Accounts
You must provide a valid email address to create an account. You are responsible for maintaining the security of your account credentials. You may link third-party chess platform accounts (Lichess, Chess.com) to import games for analysis.
3. Subscriptions and Credits
The Service offers a free tier with limited monthly credits and paid subscription plans with higher credit allowances. Subscriptions are billed monthly through our payment processor, Lemon Squeezy, which acts as the Merchant of Record for all transactions. Credits refresh monthly on the billing cycle date and do not roll over beyond one month (capped at 2x the monthly allowance).
Booster packs (one-time credit purchases) do not expire.
Prices are inclusive of applicable taxes. Lemon Squeezy handles all tax collection and remittance.
4. Right of Withdrawal (Angrerett)
Under the Norwegian Cancellation Act (Angrerettloven), you have a 14-day right of withdrawal from the date of purchase. You may cancel your subscription or purchase within this period and receive a full refund.
For digital services: by starting to use the Service (analyzing games, using credits) before the 14-day withdrawal period has expired, you expressly consent to the immediate delivery of digital content and acknowledge that you lose your right of withdrawal for credits already consumed.
Unused credits from a subscription or booster pack remain eligible for refund within the 14-day period. See our Refund Policy for details.
If you are not informed about your right of withdrawal at the time of purchase, the withdrawal period is extended up to 12 months.
5. Acceptable Use
You agree not to:
- Attempt to circumvent rate limits, credit restrictions, or security measures
- Use the Service for any illegal purpose
- Share account credentials with others
- Automate access to the Service beyond what is provided by the interface
- Attempt to extract, reverse-engineer, or abuse the AI systems
We reserve the right to suspend accounts that violate these terms.
6. AI-Generated Content
The AI commentary and explanations provided by the Service are generated by large language models and may contain errors. Chess analysis is grounded in Stockfish engine evaluations, but the natural language explanations are not guaranteed to be perfectly accurate. The Service is an educational tool, not a substitute for professional chess coaching.
7. Third-Party Services
The Service integrates with Lichess and Chess.com for game imports. We are not affiliated with either platform. Your use of those platforms is subject to their respective terms of service.
Payments are processed by Lemon Squeezy, who acts as the Merchant of Record. Lemon Squeezy is responsible for payment processing, tax collection, refund handling, and PCI compliance. Their Buyer Terms apply to all purchases.
8. Privacy and Data Protection (GDPR)
Data Controller
The controller is, within the meaning of the GDPR, the entity that defines for what purpose(s) and how your personal data is used.
The data controller is Nytt ANS, organization number 981071425, whose address is:
Nytt ANS
Vogts gate 61-2
0477 OSLO
Norway
For privacy inquiries, contact us at privacy@centipawn.app.
What We Store
| Data | Purpose | Legal Basis | Retention |
|---|---|---|---|
| Email address | Account authentication, password reset, service notifications | Contract performance | Until account deletion |
| Display name | Shown in the UI for personalization | Contract performance | Until account deletion |
| Linked platform usernames (Lichess, Chess.com) | Game imports and player identification | Consent (you link them voluntarily) | Until account deletion or unlinking |
| OAuth tokens | Secure authentication with Lichess | Contract performance | Until logout or account deletion |
| Chess game data (PGN) | Analysis by Stockfish engine | Contract performance | Until account deletion |
| AI-generated commentary | Stored so you can review analyses later | Contract performance | Until account deletion |
| Credit transactions | Billing records and credit balance tracking | Legal obligation (accounting) | 5 years after transaction (Norwegian Bookkeeping Act §13, internal ledger) |
| Session cookies | Authentication and CSRF protection | Legitimate interest (essential for service) | 14 days (encrypted) |
| IP address | Rate limiting and abuse prevention | Legitimate interest | Not stored persistently (in-memory only) |
| Salted hashes of identifiers | Fraud prevention after account deletion | Legitimate interest | Up to 1 year after deletion |
| Rating history (from linked platforms) | Tracking chess improvement over time | Consent | Until account deletion or unlinking |
| Usage statistics | Rate limiting and abuse prevention | Legitimate interest | Until account deletion |
| Training history (endgame attempts) | Tracking learning progress | Contract performance | Until account deletion |
| AI insight reports | Personalized improvement suggestions | Contract performance | Until account deletion |
| Game visibility preferences | Customizing your dashboard | Contract performance | Until account deletion |
| Debug traces (when enabled) | Diagnosing service issues | Legitimate interest | Auto-deleted after 3 days |
What We Do NOT Store
- We do not store passwords in plaintext (only bcrypt hashes)
- We do not store payment card details (handled by Lemon Squeezy)
- We do not use tracking cookies or third-party analytics
- We do not sell or share personal data with third parties
Cookies
We use only essential session cookies required for the Service to function (authentication, CSRF protection). These cookies are encrypted and expire after 14 days, or when you log out. They do not track your activity across websites. We do not use analytics cookies, advertising cookies, or any third-party tracking.
Since we use only strictly necessary cookies, no cookie consent banner is required under GDPR Article 5(3) and the ePrivacy Directive.
Sub-processors
The following third-party services process data on our behalf:
| Service | Purpose | Data Processed | Location |
|---|---|---|---|
| Anthropic (Claude API) | AI-generated chess commentary and chat | Chess positions (FEN), move sequences, user questions | United States |
| Lemon Squeezy | Payment processing (Merchant of Record) | Email, payment details | United States |
| Lichess API | Game imports (public API, no auth required) | Lichess username (public) | France (EU) |
| Chess.com API | Game imports | Chess.com username (public) | United States |
We will provide 30 days' notice before adding new sub-processors, via the Service or email.
We have data processing agreements (DPAs) in place with all sub-processors in accordance with GDPR Article 28.
Your Rights
Under the GDPR and Norwegian Personal Data Act, you have the right to:
- Access — Request a copy of all personal data we hold about you
- Rectification — Correct inaccurate personal data
- Erasure — Request deletion of your account and all associated data
- Data portability — Receive your data in a structured, machine-readable format
- Restriction — Request that we limit processing of your data
- Objection — Object to processing based on legitimate interest
- Withdraw consent — Where processing is based on consent (e.g., linked platform accounts), you may withdraw consent at any time by unlinking the account in Settings
- Lodge a complaint — File a complaint with the Norwegian Data Protection Authority (Datatilsynet) if you are unsatisfied with our handling of your data
To exercise any of these rights, contact privacy@centipawn.app. We will respond within 30 days. You will not be charged for exercising your rights.
Account Deletion
You may request complete deletion of your account and all associated data at any time. Upon deletion:
- Your email, display name, and platform usernames are permanently deleted
- All game analyses, commentary, chat history, and notes are permanently deleted
- Salted, irreversible hashes of your identifiers are retained for up to 1 year for fraud prevention. These hashes cannot be used to recover your personal data.
Fraud Prevention
To prevent abuse of the free tier (deleting and re-creating accounts to obtain unlimited free credits), we store salted cryptographic hashes of account identifiers after deletion. These hashes are one-way — they cannot be reversed to recover the original data. They are only used to detect if a new account matches a recently deleted one, and are automatically purged after 1 year.
International Data Transfers
Your personal data is primarily processed on servers located in Norway and the EU. Some data is transferred to the United States for processing by our sub-processors (see Sub-processors section above). These transfers are protected by:
- Standard Contractual Clauses (SCCs) as approved by the European Commission
- The sub-processor's own GDPR compliance measures and data protection policies
- Technical safeguards including encryption in transit (TLS 1.2+)
Data sent to Anthropic (Claude API) consists of chess positions, move sequences, and user questions — not account identifiers. Anthropic does not use this data for model training under their Privacy Policy.
Data Breach Notification
In the event of a personal data breach that poses a risk to your rights and freedoms, we will:
- Notify the Norwegian Data Protection Authority (Datatilsynet) within 72 hours of becoming aware of the breach
- Notify affected users without undue delay if the breach poses a high risk
- Document the breach, its effects, and remedial actions taken
Data Protection Officer
Due to the nature and scale of our data processing, we are not required to appoint a Data Protection Officer under GDPR Article 37. For all privacy-related inquiries, please contact privacy@centipawn.app.
Supervisory Authority
You have the right to lodge a complaint with the Norwegian Data Protection Authority (Datatilsynet) at datatilsynet.no.
9. Service Availability
We aim to provide reliable service but do not guarantee uninterrupted availability. The Service may be temporarily unavailable for maintenance, updates, or due to circumstances beyond our control.
10. Limitation of Liability
The Service is provided "as is" without warranties of any kind, except as required by Norwegian law. This does not affect your statutory consumer rights under Norwegian consumer protection legislation.
11. Governing Law
These terms are governed by Norwegian law. Any disputes shall be resolved by the Norwegian courts, without prejudice to your rights under EU consumer protection regulations to bring proceedings in your country of residence.
12. Changes to Terms
We may update these terms from time to time. Material changes will be communicated via email. Continued use of the Service after changes are posted constitutes acceptance of the revised terms.
13. Contact
For questions about these terms, contact us at support@centipawn.app.