Privacy Policy

Last updated: July 2026 · quantumchess.ninja

This policy explains what information Quantum Chess (“we”, “the site”) collects, how it is used, and the choices you have. Quantum Chess is a browser game operated by Pura Viba LLC. You can play without an account; some features are optional.

Information we collect

Account information (optional). If you create an account, we store the email address you provide, a username you choose, your game rating, and a record of your recent games. Accounts are handled through our authentication provider, Supabase.
Gameplay data. For online multiplayer, moves are relayed in real time through our server so your opponent can see them. For signed-in players, finished games (the move list and result) are saved to your account. If you explicitly share a saved game, anyone with its unguessable replay link can view that game’s moves and result; the link does not expose your email, account ID, subscription status, or other saved games.
Local storage on your device. We store small settings in your browser — a random game/client identifier, your color and display preferences, and flags such as whether you have seen the tutorial or made a privacy choice. This data stays on your device and is not an account.
Payments (optional). The Premium subscription is processed by Stripe. Your card details go directly to Stripe and never touch our servers; we store only your subscription status and a Stripe customer reference so we can activate your Premium features.
We do not collect your name, address, payment card details, or precise location.

Cookies and advertising

We may display advertising provided by Google AdSense. Google and its partners use cookies and similar technologies to serve ads and, where permitted, to personalize them based on your prior visits to this and other websites.

Third-party vendors, including Google, use cookies to serve ads based on your visits to this site and others.
Google’s use of advertising cookies enables it and its partners to serve ads to you. You can review and control this at Google Ads Settings.
You can learn about third-party ad vendors and opt out of personalized advertising at aboutads.info/choices and youronlinechoices.eu.
Optional advertising and analytics storage is denied by default. Choosing “Accept all” permits those optional technologies; choosing “Necessary only” keeps them denied and does not prevent you from playing.
Where required in the EEA, UK, and Switzerland, Google’s certified consent platform provides the additional vendor disclosures and choices required for Google advertising. Limited or non-personalized ads may be served when personalization consent is unavailable.

Third-party services

Supabase — accounts, authentication, and saved-game storage.
Google AdSense — advertising (when enabled).
Google Analytics — aggregated product and usage measurement when enabled by your privacy choice.
Amazon Web Services — website hosting and content delivery.

Each processes data under its own privacy policy.

How we use information

To run the game, including online matchmaking and real-time play.
To maintain your optional account: rating, saved games, and profile.
To remember your preferences on your device.
To show advertising that helps keep the game free.
To understand aggregated feature usage and improve the game, when analytics consent is enabled.

We do not sell your personal information.

Your rights

You can play entirely without an account and without accepting optional cookies. If you have an account, you may request access to or deletion of your data by emailing us. Depending on where you live (for example, under GDPR or CCPA), you may have rights to access, correct, delete, or restrict the processing of your personal data. You can change or withdraw your optional-cookie choice at any time through the “Privacy choices” control at the bottom of the welcome page. To clear all locally stored preferences, clear your browser storage for this site.

Children

Quantum Chess is not directed to children under 13 (or the minimum age of digital consent in your country), and we do not knowingly collect personal information from them.

Changes

We may update this policy; material changes will be reflected by the “last updated” date above.

Contact

Questions or data requests: contact@quantumchess.ninja.