Privacy
There are no accounts. Play Chess never asks for your name, email address or phone number.
Your browser's key
The first time you open a game, your browser creates a random key and keeps it in this site's storage. That is how a game knows you are the same player after a reload. The server keeps only a one-way hash of the key.
If you clear this site's data, the key is gone and this browser can no longer rejoin the games it was playing.
The game
To relay a game between two devices, the game server stores its moves, time control, clocks and result. The server runs on Cloudflare. A finished game is deleted 7 days after it ends, and a game nobody joins is deleted after 24 hours.
Anyone who opens a game's link can watch it. The link is the only way in.
Turn notifications
Turn notifications are shown by this browser, from the game you left open. Nothing is stored on the server for them.
Puzzles
Your puzzle progress (how many you have solved, the days you solved the daily puzzle and where you are in each level) stays in this browser's storage. It is not sent anywhere.
A game against the computer (level, your colour and the moves played) is also kept only in this browser's storage, so you can carry on after a refresh. Starting a new game replaces it.
A two-player game on one device is kept the same way, only in this browser.
The best score in 3-minute puzzles is kept only in this browser as well.
Your record against each computer level (wins, losses, draws) is kept only in this browser too.
Your last 30 finished games (moves and results) are also kept only in this browser, for the My games page. Clearing them there deletes them.
Which lessons you have finished in Learn is also kept only in this browser.
Which drills you have completed in Train is also kept only in this browser.
Advertising
Pages other than the board and the puzzles show adverts through Google AdSense, which may set cookies and use them to personalise ads. You can turn personalised ads off in Google Ads Settings (adssettings.google.com).
Contact form
What you send through the contact form is kept as a post in a private GitHub repository that only the operator can read, so it can be answered. A reply address is optional; without one there is no way to write back.
Traffic measurement
We use Firebase Analytics (Google) to measure visits and how pages are used. It uses cookies and device identifiers and sends usage data to Google. It does not receive your moves. It loads after the page has finished loading; if it is blocked, games still work.
Google Analytics opt-out browser add-on
YouTube
The home page shows the app trailer from YouTube, a Google service. Until you press play, only the preview image loads from YouTube; the video player loads from youtube-nocookie.com only after you press it. Google Privacy Policy
Mobile app
The Play Chess app for Android and iOS sends the results of your games to our server (api.play-chess.co): the game number, whether you finished it, how long it took, how many moves, hints and undos you used, and how many ads you watched.
These results are stored with a random installation ID that the app creates. It is not linked to your name, email address or advertising ID, and the app has no accounts.
The app also sends its notification token (if it has one), whether notifications are allowed, the hour you usually play and your time zone, so that it can send a daily reminder and a gift when you come back.
We use these results to measure how difficult each game is and to offer games at the right difficulty. They are not sold or shared with advertisers. Uninstalling the app stops all sending.
Usage statistics (Google Analytics for Firebase)
The Play Chess app also sends usage statistics to Google Analytics for Firebase, a service run by Google: when a game starts and ends, how long it took, whether you won, the mode and score, how much help (hints or continues) you used, and when an ad would show, is skipped, or a reward ad is offered or watched. The Firebase SDK also records on its own when the app is opened and for how long, the app version, the device model and operating system, and an approximate location (country or region) that Google works out from the connection. For each ad shown it also sends the ad’s estimated value and the ad network that provided it, and it sorts players into broad groups by how often they play and how well they do.
To count devices, the Firebase SDK creates a random app-instance ID for each installation; on iOS it also reads the identifier for vendor (IDFV). The app does not let Firebase collect the Android advertising ID or the iOS advertising identifier (IDFA). We use these statistics only to improve the game and do not sell them. Uninstalling the app removes the app-instance ID from your device.
After you install the Android app from Google Play, it asks Google Play once where the install came from (the Play Install Referrer) and sends that to Firebase: the source, medium and campaign named in the store link, whether it followed a Google Ads click, and a short label such as a link on our website. We use this only to measure which store links and campaigns bring installs.
Firebase privacy and security · Google Privacy Policy
Ads (Google AdMob, Android)
The Android app shows full-screen ads between games and reward ads that you can choose to watch, for example to get more hints. The ads come from Google AdMob, a service run by Google. AdMob is first set up right before the first ad would show, not when you first open the app; after that it starts when you open the app.
When AdMob is set up, people in the European Economic Area, the United Kingdom and Switzerland are asked about ads and data in a consent form from Google. You can play either way and change your choices later under “Privacy choices” in the app’s settings.
To show and measure ads and to prevent fraud, the Google Mobile Ads SDK collects the IP address (which may be used to estimate the general location of the device), your interactions with the app and its ads, diagnostic information about the app and the SDK, and device identifiers such as the Android advertising ID and app set ID. You can reset or delete your advertising ID in your Android settings.
If you buy the “Ad-free pass”, Google Play handles the payment. The pass lasts 1 week, 3 months or 1 year and does not renew on its own. While it lasts there are no ads, including reward ads, and when you run out of hints you get 3 more once a day. The app only asks Google Play whether your pass is active, so it keeps working after you reinstall.
Google’s data disclosure for the Mobile Ads SDK · How Google uses information from sites or apps that use its services