Privacy Policy
Counterfoil · last updated 19 August 2026
What we collect
Counterfoil is built to collect as little as possible.
- No account data. We do not ask for your name, email address, or password to play.
- On your device. Your progress, collection, and player key are stored in your browser’s local storage on your own device. We cannot read this.
- On our server. When you register cards or currency, we store your public player identifier, the serial numbers assigned to it, and transaction records. A public identifier is not your name and is not linked to your identity by us.
- Multiplayer. While connected, your chosen display name and in-world position are relayed to other players present.
- Server logs. Our web server records IP address, request path, and timestamp, kept for security and troubleshooting, typically for 30 days.
- Payments. Card details are collected and processed by Stripe, never by us. We receive a payment confirmation and the identifier to credit. See Stripe’s privacy policy at stripe.com/privacy.
What we do not do
We do not sell or rent your data. We do not use advertising or third-party tracking. There are no analytics cookies.
Public information
The card ledger and currency supply are published so that the economy can be audited by anyone. These pages show serial numbers, public identifiers, and transfer history — never names, emails, or payment details.
Your rights
Depending on where you live you may have rights to access, correct, or delete personal data we hold. Because we hold so little, most requests concern payment records, which we retain as long as tax and accounting law requires. Write to support@theriemannhypothesis.com.
Children
The game is not directed at children under 13, and we do not knowingly collect personal information from them.
Contact
support@theriemannhypothesis.com