Welcome to Chess Pi! This Privacy Policy explains how we handle your information when you use our chess application. Your privacy is important to us, and we are committed to protecting your personal data.
Note: Chess Pi runs mostly in your browser, but signing in with Pi Network and using paid features (Premium, the Starter Offer, or unlocking themes/levels/piece sets/bot personalities) requires us to store a small amount of data on our servers so your unlocks, subscription, and leaderboard entry follow you across sessions and devices.
1. Information We Collect
a) Information From Pi Network Sign-In
Chess Pi does not have its own account system or password. Instead, you sign in through the Pi Network SDK, which shares the following with us (with your permission, via the "username" and "payments" scopes):
- Your Pi Network username
- Your Pi Network user ID (UID), a unique identifier tied to your Pi Network account
- An access token used to verify your identity with Pi's own servers on each request — we never receive or store your Pi Network password or wallet keys
b) Game Progress and Purchases (Stored on Our Servers)
Once signed in, the following is saved on our servers, keyed to your Pi Network UID, so it's available whenever you return:
- Unlocked/purchased difficulty levels, board themes, piece sets, and bot personalities
- Your Chess Pi Premium subscription status and expiration date (including Starter Offer eligibility and how many introductory cycles you've used)
- Win/loss statistics, games played, win rate, and a difficulty-weighted score used for the public leaderboard
- Payment records needed to verify and complete Pi Network transactions (see Section 4)
c) Information Stored Locally On Your Device
The following stays in your browser's local storage and is never sent to our servers:
- Game preferences (theme, language, difficulty level) when you're not signed in, or as a working copy of your synced progress
- The current game in progress (board position, move history)
- PGN files you choose to import for game analysis
d) Third-Party Services
We use the following third-party services:
- Pi Network SDK for sign-in and processing Pi cryptocurrency payments
- chess.js and a Stockfish-based engine for game logic and analysis, running entirely in your browser
- i18next for internationalization
- Font Awesome for icons
- Netlify for application hosting, serverless functions, and encrypted data storage (Netlify Blobs)
These services may collect information as described in their respective privacy policies. In particular, your use of the Pi Network app and any Pi cryptocurrency transaction is also governed by Pi Network's own privacy policy and terms.
2. How We Use Your Information
We use the information we collect for the following purposes:
- To provide and maintain the chess game functionality
- To keep your unlocked content, Premium/Starter Offer subscription, and progress in sync across sessions and devices
- To verify and process Pi Network payments, and to prevent fraudulent or duplicate payment claims
- To display your username, win/loss record, and score on the public leaderboard, if you choose to play ranked games
- To apply basic rate limiting and anti-abuse checks (by UID and/or IP address) to protect the service from automated abuse
- To improve game performance and user experience
3. Data Storage and Local Processing
Chess Pi splits data storage between your device and our servers:
- The chess engine, move validation, and PGN import/export all run locally in your browser — no board position or move data is sent anywhere unless you submit a completed game's result to the leaderboard
- Signed-in progress, purchases, and leaderboard data described in Section 1(b) are stored server-side in Netlify Blobs, associated with your Pi Network UID
- If you are not signed in, your preferences and progress are stored only in your browser's local storage and are not sent to us
4. Payment Processing
Chess Pi offers several optional paid features via the Pi Network payment system: the Refill feature, unlocking individual or bundled themes/levels/piece sets/bot personalities, Chess Pi Premium (monthly or yearly), and the introductory Starter Offer. For all of these:
- Payment initiation and processing is handled by the Pi Network app/SDK — we never see or store your Pi wallet keys or seed phrase
- Our servers verify the payment amount and your identity directly with Pi Network's servers before approving and completing any transaction
- We store a record of the transaction (amount, product purchased, Pi payment identifier, and timestamp) so we can grant, verify, and — if needed — reconcile your purchase or subscription
- Payments are processed and finalized through Pi Network; see also Section 4 of our Terms of Use regarding refunds
5. Data Sharing and Disclosure
We do not sell, trade, or otherwise transfer your personal information to third parties except in the following circumstances:
- With your explicit consent
- When required by law or to comply with legal processes
- To protect our rights, privacy, safety, or property
- With service providers who assist in our operations (currently Pi Network, for payment verification, and Netlify, for hosting and data storage), under the confidentiality and data-processing terms of those platforms
- Your Pi Network username, win/loss record, and score are shown publicly on the in-app leaderboard to anyone who views it — this is a visible part of the leaderboard feature itself, not a third-party disclosure, and you can avoid it by not playing ranked games while signed in
6. Data Security
We implement appropriate security measures to protect your information:
- All identity verification is checked server-side directly against Pi Network's API — your UID is never trusted from data the client sends on its own
- Server-issued, cryptographically signed tokens (rather than client-supplied values) are used to prevent tampering with game results, scores, or payment amounts
- Rate limiting on sign-in, payment, and score-submission endpoints to reduce automated abuse
- Secure (HTTPS) communication for all data transmitted between your browser and our servers
However, please note that no method of electronic transmission or storage is 100% secure.
7. Your Rights and Choices
Depending on your location, you may have the following rights regarding your personal information:
- Access and receive a copy of your personal data
- Correct inaccurate or incomplete information
- Delete your personal data (including your leaderboard entry and stored progress) from our systems
- Object to or restrict the processing of your information
- Data portability (receiving your data in a structured format)
To exercise these rights, please contact us using the information provided below.
You can clear any locally stored preferences and in-progress game data by clearing your browser's cache and local storage for our application. This does not delete progress already saved to our servers under your Pi Network UID — contact us to request deletion of that data.
8. Children's Privacy
Chess Pi is suitable for all ages, but signing in, making purchases, and appearing on the leaderboard require a Pi Network account, which has its own eligibility requirements. We do not knowingly collect personal information from children under 13 outside of what Pi Network itself provides during sign-in. If you believe we have inadvertently collected such information, please contact us immediately so we can remove it.
9. Changes to This Privacy Policy
We may update this Privacy Policy from time to time. We will notify you of any changes by posting the new Privacy Policy on this page and updating the "Last Updated" date. You are advised to review this Privacy Policy periodically for any changes.
10. Contact Us
If you have any questions or concerns about this Privacy Policy or our data practices, please contact us: