Privacy Policy
Last updated: 8 October 2026
Short version: Chess Drills only stores what it needs to run your account and your training. There are no ads, no trackers and no analytics, and we never sell your data. You can download or delete your data at any time in Settings.
Who we are
Chess Drills is made by Rutger van Doren, based in the Netherlands. For any question about your data, email herdsadmin@gmail.com.
What we store and why
| Data | Why | Legal basis |
|---|---|---|
| Username, email address, password (stored only as a secure hash) or, if you sign in with Google, your Google account ID | To create your account, log you in and help you reset your password | Contract |
| Your drills, chapters, review schedule and results | To provide the training, Daily Review and progress | Contract |
| If you connect them: your Chess.com and/or Lichess username, your preferred playing style, and copies of your public games from those sites (date, colour, result, ratings, opponent's username and the first 20 moves) | To analyse which openings you play, recommend openings to study and show your statistics. You can disconnect at any time; the imported games are then deleted | Consent |
| If you turn on the daily reminder: the chosen time, your time zone and a technical address from your browser or phone to deliver the notification | To send you one reminder a day when there is something to practise. You can turn it off at any time in Settings | Consent |
| Settings (theme, board, sound, new chapters per day) | To show the app the way you chose | Contract |
| Sign-up date, the days on which you used the app, date you accepted these terms | To run and improve the service (for example counting active users) and to keep records | Legitimate interest |
| Usage counter: day, platform (Android app, iPhone home screen or website) and a random device code | To know which versions of the app are used, so we know what to improve | Legitimate interest |
| Failed login attempts (IP address, kept only in memory for 10 minutes) | To protect accounts against password guessing | Legitimate interest |
Cookies and local storage
We use one functional cookie that keeps you logged in. Your browser also remembers a few interface choices on your own device (such as sorting in your library and the explorer database). We do not use advertising or tracking cookies, so no cookie banner is needed.
Usage counter. To know whether people use the Android app, the iPhone home screen app or the website, your browser creates a random code (not linked to your name or email) and tells our own server once per visit which of these you used. We store the day, the platform and that code, plus your username if you are logged in, and keep it for at most 12 months. Nothing is shared with anyone else.
Who else receives data
- Google (only if you sign in with Google): Google tells us your name, email address and a Google account ID. We store the email address and the ID to recognise you, and use your name once to suggest a username. We get no access to your Google account, contacts or other data.
- Hosting: the app and database run at Contabo GmbH (Germany), within the European Union. They process data only on our behalf.
- Lichess: to show opening statistics, our server sends the chess position (no personal data) to the lichess.org opening explorer.
- Chess.com and Lichess (only if you connect an account): our server asks chess.com and lichess.org for the public games of the username you entered. We send them only that username. Chess Drills is not affiliated with Chess.com or Lichess.
- Notifications (only if you turn on the daily reminder): the reminder is delivered through the push service of your browser or phone (for example Google for Chrome and Android, Apple for Safari). It is encrypted; they cannot read its content.
- Backups: every night a backup of the database is encrypted on our server and then stored in Google Drive. It is encrypted before it leaves our server; Google cannot read it.
- Email: if you ask for a password reset, our email provider sends that one email to you.
We do not sell or share your data with anyone else, unless the law requires us to.
How long we keep data
We keep your data as long as you have an account. When you delete your account, your account and all data (training data and imported games) are deleted immediately. Backups that still contain your data are deleted automatically within 60 days.
Deleting your account
You can delete your account and all your data yourself: log in, go to Settings → Delete account and confirm with your password. Can't log in anymore? Email herdsadmin@gmail.com from the email address of your account and we will delete it within 30 days.
Deleted: your account (username, email address, password hash), linked Chess.com and Lichess usernames, imported games, your drills and training history, settings, activity days and reminder subscriptions. Kept: nothing. Encrypted backups that still contain your data are deleted automatically within 60 days.
Your rights
You can view and change your data in the app, download all of it (Settings → Download my data) and delete your account. You may also ask us for access, correction, deletion, restriction or objection by email. If you are not happy with how we handle your data, you can complain to your data protection authority; in the Netherlands that is the Autoriteit Persoonsgegevens.
Children
Chess Drills is meant for players aged 13 and older. If you are under 16, please ask a parent or guardian for permission before creating an account.
Security
Passwords are stored as secure hashes, the connection is encrypted (HTTPS) and access to the database is restricted. No system is perfect; if something goes wrong that affects you, we will tell you.
Changes
If we change this policy, we update the date at the top. For important changes we will let you know in the app.