Privacy, in plain language.

Sign-in and your player identity

Google sign-in supplies your Google account identifier, verified email address, and display name. We use these to identify your account and sign you in. Your display name, or email prefix if a name is unavailable, helps create your initial public username. You can change your username and chosen country in Profile.

The database stores your Google identifier, email, username, country, and account creation time. Your email address and Google identifier are not displayed on public profiles or leaderboards. Google access tokens are used to complete sign-in and are not saved in the app database.

Game records and what other people can see

Online play stores match and room participants, settings, submitted equations, scores, timings, and rating results to run games, prevent duplicate actions, and keep match history. Your public username, country flag, ratings, game statistics, and recent finished-match summaries can appear on profiles and leaderboards. Your opponent can see your submitted equation and score after the round is revealed; match participants can review completed rounds.

Practice without signing in and the learning lab run their calculations in your browser. Shared calculator links include equations in the URL, so anyone with the link can read them.

Cookies and information on your device

• The sign-in cookie, gg_session, identifies a server session that expires after 30 days. Signing out deletes the current server session and clears its cookie.
• The temporary Google sign-in cookie, gg_oauth, protects the sign-in flow and remembers where to return you. It expires after 10 minutes and is cleared when the callback is handled.
• Equation drafts, local practice runs, and remembered room codes use browser session storage. XP, badges, streaks, personal bests, saved learning-lab equations, and sound settings use local storage on your device.

You can remove these browser records through your browser’s settings by clearing GraphDuel’s cookies and site data. This also removes locally saved progress and graphs. Signing out alone does not clear that data or delete your account.

Free player styles and billing

Every game mode, learning tool, and player style is currently free. Your selected profile style is saved to your account and can appear on your public profile. Checkout is disabled; choosing a style does not create a subscription or sign you up for future charges. The app does not collect or store payment-card numbers.

A billing integration is prepared for a possible future change. If paid memberships are offered later, their terms and use of Stripe will be explained before you choose to subscribe. Adding a payment provider does not automatically enable charging.

Hosting and security

Vercel hosts and delivers GraphDuel, Neon stores the online database, and Google provides sign-in. These providers process information needed for those services. Requests can include operational metadata such as IP addresses, browser information, requested URLs, and error or security events. Vercel’s bot protection helps identify automated traffic. The app also keeps account-based request counters to limit abuse.

Retention and your choices

Account and match records are retained to operate player identities, ratings, and history. There is no automatic account or match-history expiry. Maintenance periodically removes expired sessions and request counters, stale queue records, and old waiting rooms.

For questions about your information, or to request account-data deletion, contact GraphDuel at shobhitdhamania@gmail.com. Include your public username so we can identify the account. We may ask you to verify account ownership before acting on a request.