Privacy Policy
Blindgrade · effective 28 August 2026
Blindgrade (blindgrade.com) is a daily chart-trading guessing game. This page describes what data the game collects and what happens to it. Questions: admin@blindgrade.com.
What we collect
Playing without an account: a session cookie holding a random identifier, and the gameplay history (rounds, trades, scores) tied to it. Nothing that directly identifies you — no name, email, or profile.
Creating an account (optional): your email address. If you sign in with Google, we also store your Google account identifier. We do not request or store your name, photo, or contacts.
We do not run advertising, and we do not use third-party analytics or tracking.
Google sign-in
Signing in with Google requests only the openid and
email scopes. The email address and account identifier
Google provides are used solely to create and sign you into your
Blindgrade account. We do not share, sell, or transfer this data to
third parties, and we do not use it for advertising. Blindgrade's use
of information received from Google APIs adheres to the
Google API Services User Data Policy, including the Limited Use requirements.
Cookies
One persistent cookie: the session identifier that keeps you signed in and links your rounds together. During Google sign-in, a second short-lived cookie holds a security token for a few minutes. Both are strictly necessary for the game to work. There are no tracking or advertising cookies.
If you sign in by magic link, we send that one email through a transactional email provider. We do not send marketing email.
Sharing
Your data lives on our hosting, database, and content-delivery network infrastructure and with the email provider above, each acting only on our instructions. We never sell personal data, and we disclose it only if required by law.
Retention and deletion
Account data is kept while your account exists. Anonymous session data is kept so your history survives return visits. Email admin@blindgrade.com from your account address to have your account and its data deleted; you can also ask for a copy of your data or a correction at the same address.
Children
Blindgrade is not directed at children under 13.
Changes
If this policy changes, the new version is posted here with an updated effective date.