Privacy Policy
- Effective date: 7 October 2026 (updated the same day: no pictures)
- Operator: Daniel Feldman, who runs Thumbprint School at https://thumbprint.school
- Contact: privacy@thumbprint.school
Every statement below describes what the site does today.
The short version
- You can play every game as an anonymous guest. We do not ask for your name, email or age to play.
- We set one cookie that keeps your guest session, so your scores stay with your browser.
- We never store your IP address. We keep only a scrambled value that changes every day, used to stop abuse.
- Clay Mail messages are private, locked behind a PIN, and deleted automatically within 48 hours.
- Nothing anyone writes is ever public or browsable.
- We do not sell your information and we do not show ads today.
What we collect
When you play as a guest
- A random session identifier, stored on our server and in a cookie on your device (see Cookies).
- Your game scores, linked to that random session identifier. The leaderboard shows guests as "Anonymous".
- Settings you choose, such as sound, motion and filters. These stay in your browser's local storage and never reach our server.
- Some games keep progress on your device, for example the Neon Lanes armory. This also stays in your browser.
When you create an account
Accounts store:
- a username and display name;
- a password, stored only as a salted scrypt hash;
- optionally passkeys: we keep only each passkey's public key, a name you choose, a usage counter and when it was added and last used (the private key never leaves your device);
- your birth month and year, used only to check you are at least 13 and whether you are 18 or older.
An account made with a username and password has no email address.
When you sign in with Google
If you choose "Continue with Google", Google tells us your Google account's identifier, your email address, whether Google has verified it, and your name. We keep the identifier (to recognise you next time) and the email address (on your account, and to link a Google sign-in to an account with the same verified address). Your name is used only to suggest a username, which you can change. You still give your birth month and year, the same 13-or-older check as every account; whether you are 18 or older is never taken from Google. We ask Google for nothing else, and Google learns nothing from us beyond the fact that you signed in here.
Clay Mail (in-game terminals)
Clay Mail lets players leave a short message that someone else can read with a PIN at an in-game terminal. For each message we store:
- the message text, checked by a word filter before it is accepted;
- a one-way hash of the PIN (never the PIN itself);
- the constraints the writer chose, for example which game or terminal can open it, who may read it, and how many times;
- the writer's random session identifier and a daily scrambled network value, used only for abuse prevention and reports;
- when it was created and when it expires.
Messages are deleted at the earliest of three moments:
- 48 hours after they were written;
- when they have been read the number of times the writer allowed;
- when two different players report them.
Messages are never listed, searched or shown publicly. There is no way to browse other people's messages.
Clay Mail takes no pictures: the site accepts no image uploads at all. If you report a message, a copy of its words and link is kept for our review for 30 days. If we remove a message, its sender cannot use Clay Mail for 7 days. Our database backups never contain Clay Mail messages, and our logs never contain your IP address: only a code derived from it that changes every day. A message can also carry one https link. It is shown as text, checked against our blocklist and Google Safe Browsing (which receives the link but nothing about you), and opened only after you confirm that you are leaving the site.
Network information
Our server sees your IP address on every request, as all websites do. We do not store it. To limit abuse, such as message spam, we keep a keyed hash of it. The key changes every day, so the value cannot be linked from one day to the next. Rate-limit counters live only in the server's memory and disappear within minutes.
A message can be limited to a place: "only readable in my country", "my region" or "my city". When you choose one, our server looks up the place your IP address belongs to (a database on our own server, nothing is sent to anyone else) and saves only that place's name with the message, never your address. When someone tries to read a limited message, their address is looked up the same way, in memory, and not kept. The place of an address is approximate, so a limited message may not reach someone just over a border. This feature is switched on only when our location database is installed; otherwise the option is not offered.
This product includes GeoLite2 data created by MaxMind, available from https://www.maxmind.com.
Cookies
We use one cookie, clay_sid. It is strictly necessary to keep your session.
- It is HttpOnly, so scripts cannot read it.
- It is SameSite=Lax, and Secure over https.
- It lasts 30 days for guests and 90 days for accounts.
We do not use advertising, analytics or third-party cookies. The site loads no third-party scripts, fonts or trackers.
The site can also be installed as an app. When you play, your browser keeps copies of the site and of games you have played, so they work offline. Your personal data is never part of this cache.
How we use information
- To run the games and keep your scores.
- To deliver Clay Mail to the person with the PIN, under the rules the writer chose.
- To prevent abuse: rate limits, word filters and reports.
- To keep Mature (M) games hidden from guests and from accounts that have not shown they are 18 or older.
We do not use your information for advertising or profiling, and we do not sell or rent it.
Children
The site is designed to be suitable for teens, with adult presentation.
- Guests are anonymous, and no personal information is requested to play.
- Accounts require a declared age of 13 or older; a younger birth date is refused and nothing is kept.
- Mature games are hidden unless an account indicates 18 or older.
We do not knowingly collect personal information from children under 13. A guest's session cookie and scores identify no one. If you believe a child under 13 has given us personal information, write to privacy@thumbprint.school and we will delete it.
Your choices
- "Forget me" in the arcade deletes your session from our server and clears the cookie. Your past scores then can no longer be linked to you.
- You can clear the site's local storage and cache from your browser settings at any time.
- Signed-in players can download everything held about their account, and delete it (with their password), from the account page. Deleting removes the account, its scores, saved game progress, sessions and any Clay Mail it wrote.
How long we keep information
| What | How long |
|---|---|
| Clay Mail messages | 48 hours at most (sooner when read out or reported) |
| Reports | 30 days |
| Sessions | Until "Forget me" or account deletion; a session unused for 30 days (guests) or 90 days (signed in) is removed from the server automatically |
| Scores | While the service runs, or until you delete your account |
| Daily scrambled network values | Stored with messages, so 48 hours at most |
Where data is stored
On one server we rent from Fly.io, in the United States (Virginia), with an encrypted disk and daily snapshots. Fly.io runs the machine; it does not use your information for anything of its own. Our domain's name service and our email forwarding are run by Cloudflare.
Changes
We will post changes here and update the effective date.
Contact
privacy@thumbprint.school