Privacy Policy

1. What We Collect

The information we collect depends on how you use Tug of Math:

Without an account

You can play without creating an account, both on the web and in the app. We still record the following:

• A random identifier generated on your device. It is not taken from your hardware and it is not an advertising identifier. It is what lets us count the free games a device has played, and what connects games played before sign-up to your account if you later create one.
• The result of every game, sent to our servers under that identifier: the settings you chose, how long the game took, the scores, and a record of the answers given. If you type names for the two teams, those names are stored with the result.
• Game settings and preferences stored locally on your device
• Usage data, described in sections 3 and 5. On the website this is anonymous and collected only if you accept cookies.
• A cookie consent preference stored in your browser (website only)

With an account

• Your name and email address
• Your password (stored securely using one-way encryption)
• Your language preference
• Avatar URL (if provided)
• If you sign in with Google, Microsoft or Apple: your provider account ID. Sign in with Apple may give us a private relay address in place of your real email address.
• Game session data: settings, duration, scores, player names, and results
• Saved game presets and custom problem sets
• Organization membership and role (if applicable)
• If you subscribe: which plan you hold, which store you bought it from, and when it renews or expires

2. How We Use Your Information

• To provide and maintain the game service
• To authenticate your account and manage your session
• To save your game settings, presets, and problem sets
• To display your game history and statistics
• To count the free games a device or an account has used, and to check what a subscription entitles you to
• To process payments and manage subscriptions
• To send essential emails (account verification, password resets, organization invitations) and product updates and tips
• To understand how the game is used and improve it (via analytics)

3. Third-Party Services

We use the following third-party services:

• Google Analytics 4 — anonymous usage analytics on the website (only with your consent)
• Google Analytics for Firebase — usage analytics in the app, with every advertising feature turned off
• PostHog — product analytics in the app, hosted in the European Union
• Stripe — payment processing for subscriptions bought on the web. Stripe handles all payment card data; we only store the last 4 digits and card type.
• Apple App Store and Google Play — payment processing for anything bought inside the app. They take the payment and hold your payment details; we never see them.
• RevenueCat — records app store purchases and tells us which subscription an account holds
• Google OAuth — if you choose to sign in with Google
• Microsoft OAuth — if you choose to sign in with Microsoft
• Sign in with Apple — if you choose to sign in with Apple
• PartyKit — real-time multiplayer game connections
• Resend — email delivery for account notifications, product updates, and invitations
• Cloudflare — website hosting and content delivery

We do not sell, rent, or share your personal data with advertisers or data brokers.

4. Cookies & Local Storage (website)

On the website we use minimal cookies and local storage:

• Cookie consent preference (localStorage)
• CSRF protection cookie (essential, for authenticated users)
• Session cookie (essential, for authenticated users)
• Game settings and saved problem sets (localStorage)
• Google Analytics cookies (only if you accept)

You can decline non-essential cookies via our cookie banner. The game works fully without them.

5. The App

Everything in this policy applies to the Tug of Math app for iPhone, iPad and Android. A few things work differently there than on the website:

• The app uses no cookies and has no cookie banner. Settings and preferences are stored on the device itself, and your sign-in token is held in the device's secure store: the Keychain on iOS, the Keystore on Android.
• The app shows no advertising. We do not collect the advertising identifier on either platform, and every advertising feature of the analytics tools we use is switched off.
• You can play, and buy a subscription, without giving us an email address. When you do, the account belongs to the device and is identified only by the random identifier described in section 1. If you later sign in, it is linked to your real account so that your games and your purchase come with you.
• The app measures a short and fixed list of events: a game started, a game finished, the paywall opened, a free-game limit reached, and a review being asked for. It does not record what you type, does not capture screen recordings, and does not track individual taps. These events carry the device identifier, and are linked to your account once you sign in.
• Because there are no cookies there is no cookie banner, and this measurement is on by default. If you would rather we did not measure your use of the app, write to us at [email protected].
• Purchases are made through the App Store or Google Play. We receive a record of what was bought and when it expires, never your payment details.
• You can delete your account from Settings inside the app. Section 6 describes what that does.

6. Data Retention

• Account data is kept as long as your account is active
• Game session data is kept linked to your account for as long as your account exists
• Games played without an account, and the device accounts described in section 5, are kept indefinitely. They carry no name, email address, or other contact detail.
• When you delete your account we immediately remove your name, email address, avatar and password, delete your sign-in tokens and any linked Google, Microsoft or Apple account, and keep an empty placeholder in its place so that the records that referred to it stay consistent
• Your game history is not deleted with your account, it is disconnected from you. Your account and the device identifier are removed from every game, and any player name recorded against an answer is erased. Team names typed into a game are saved as part of its settings and stay with the result, which is why we ask you to use first names or nicknames. What remains is a set of results with nobody attached, and we keep those because the totals we publish are counted from every game ever played.
• Data held on your own device can be cleared at any time through your browser settings, or by deleting the app

7. Your Rights (GDPR)

If you are in the European Economic Area (EEA), you have the following rights:

• Access — request a copy of the personal data we hold about you
• Rectification — ask us to correct inaccurate data
• Erasure — ask us to delete your account and data
• Portability — receive your data in a machine-readable format
• Objection — object to data processing based on legitimate interests, including the app measurement described in section 5
• Withdraw consent — withdraw cookie consent at any time via the cookie banner on the website

To exercise any of these rights, contact us at [email protected].

8. Children's Privacy

The website is built for classrooms. The whiteboard game needs no account, and accounts on the web are intended for teachers and educators. The only student information that can reach us there is a name: one typed in as a team name, or one attached to an answer when a teacher runs a game with a class roster.

The app is built for families, and the people playing it are usually children. It is designed so that a child never has to tell us anything about themselves: there is no chat, no profile, no photo upload, no advertising, and no sign-in needed to play.

The account, the subscription and the purchase all belong to the adult. You must be at least 16 years old to create an account or make a purchase, and children should play under the supervision of a parent or guardian.

In the app, the only way a child's information reaches us is through the names typed in for the two teams, which are saved with the game result. We would rather you used first names or nicknames there than full names.

Beyond that we do not knowingly collect personal information from children. If you believe a child has given us personal data, contact us at [email protected] and we will delete it.

9. Security

We take reasonable measures to protect your information, including encrypted passwords, HTTPS encryption, CSRF protection, and rate-limited authentication endpoints. In the app, your sign-in token is held in the device's own secure store rather than in ordinary storage. However, no method of transmission over the internet is 100% secure.

10. Changes to This Policy

We may update this Privacy Policy from time to time. We will notify you of significant changes by posting the new policy on this page with an updated date.

11. Contact

If you have questions about this Privacy Policy, contact us at: