Privacy
Last updated 26 October 2026. Em português.
This page says exactly what this site stores and why. It is written from the code, not from a template, so if something here is wrong the code is wrong too.
You can play without giving us anything
Opening the site creates a guest player so the board works immediately. That
guest has an invented name like guest-7f3a and no email address. You
can play against the machine and against other people as a guest for as long as
you like.
What is stored
| What | When | Why |
|---|---|---|
| A session token, stored as a one-way hash | The first time you open the site | So the same browser returns to the same player. It is kept in a cookie that scripts cannot read, and the database never holds the token itself, only a digest of it. |
| A player name | Created with the session; you may change it | So other players can see who they are playing. |
| A two-letter country code | Once, when the player is created | For the per-country leaderboard. It comes from the country our network provider works out from your connection. We do not store your IP address for this, and the code is never narrowed to a city. |
| Your email address | Only if you choose to sign in | It is the only way to recover your account on another device. We do not send marketing, we do not sell it, and nothing else is attached to it. |
| Your games: moves, times, result and rating change | As you play | So a game can be resumed and reviewed, and so ratings and leaderboards can be computed. |
| Your rating and win, loss and draw counts | After each rated game | The leaderboards. |
| Chat messages | Only while the game is being played | They live in the server's memory for the length of the game and are never written to the database. When the game ends they are gone. |
What is not stored
- No password. Signing in uses a code sent to your email, so there is no password to leak.
- No payment details. Nothing on this site is paid for.
- No advertising or tracking profile. There are no advertising cookies and no third-party tracker on the pages you play on.
- No chat history after the game ends.
Cookies
One cookie, c3d_session. It holds the session token described
above, is marked so that page scripts cannot read it, is sent only over HTTPS,
and expires after 90 days. It is what keeps you signed in; there is no way to
offer that without it, so there is no consent banner asking about it. Your theme
and language choices are kept in your own browser's local storage and never
reach us.
Who else touches your data
- Cloudflare sits in front of this site and routes every request. It sees the connection, supplies the country code described above, and counts page views. Its own privacy terms apply to that.
- Our sign-in service is run by us on our own servers and is
the only thing that handles your email address. The code that reaches your
inbox is sent from
[email protected]by our own mail server, not by a third-party email provider.
Nothing is sold, rented or shared with anyone else.
How long it is kept
A guest player that is never used again is kept as long as its games are, so that past opponents' game records stay complete. A signed-in account is kept until you ask for it to be deleted.
Your choices
- See what we hold. Your profile shows your name, country, rating and games.
- Correct it. You can change your player name yourself.
- Delete it. Write to the address below and your account, your email address and your rating are removed. Games you played stay, with your name replaced by a deleted-player marker, because the other player's record of their own game is theirs too.
- Sign out everywhere. Signing out invalidates the session on that device.
If you are in a place whose law gives you rights over your data, such as the GDPR in Europe or the LGPD in Brazil, those rights apply here and the list above is how they are exercised.
Children
This site is not aimed at children under 13 and we do not knowingly keep an account for one. If you believe a child has created an account, write to us and it will be removed.
Contact
Write to [email protected] for anything on this page, including deletion.
Changes
If this notice changes in a way that affects what is stored or who sees it, the date at the top changes and the change is described here.