Privacy
The short version
There are no accounts, no sign-ups and no emails. We never ask for your name, age or date of birth, your rank is not tied to who you are, and nothing here builds a profile of you. The one exception is the Android app: before its first ad it asks your age once, keeps only "under 13" or "13 and over" on your phone, and never sends it to us.
What the game sends us
When you finish a level, your browser sends the moves you made, with their timing, and a one-time ticket for that run. The server replays the moves to check your time, adds the time to an anonymous count of everyone’s times on that level, and does not keep the moves. Each ticket is remembered for three days so it cannot be used twice. A challenge link stores the level, its layout, the time to beat and how many attempts it has had, and stops working after 30 days. The game also tallies, per day and per level, how often it is opened, played, finished and shared — totals, nothing more. When you leave a level unfinished, it also adds how long that run lasted, in whole seconds, to an anonymous count for that level.
What your browser keeps
The game keeps its state in your own browser: the levels you have finished, your best medal on each, your settings (sound, volume, graphics quality, vibration, motion), the mute switch and the tips you have already seen, plus one flag that lasts only until you close the tab. The chess pages keep your list of looked-up players the same way. None of it is sent to us unless you turn on cloud save (below), and clearing this site’s data resets it. While you play, the game also asks your device to keep the screen on — a request to your browser, not something we record. It also remembers the last day you visited and the last day you played. Once a day your browser sends only "new" or "returning", and "played today", so we can count visitors and players per day. Unless you turn on cloud save, no identifier ever leaves your browser.
Cloud save (optional)
Off unless you turn it on. Your browser also keeps your best time and accuracy on each level and how many runs you have finished; like everything above, that stays on your device until you turn cloud save on. When it is on, we store your game progress (best times, medals, settings) under a random key that only your devices hold. Our server keeps a one-way code of that key, never the key itself, plus a random id for each device or browser you use, which says nothing about you. If you link Google, we store a one-way code derived from your Google account ID, never your email, name or photo. A transfer code works once and expires after 15 minutes. Delete it any time in Settings. It's gone from our server immediately.
Delete your cloud save
In the game or the app: Settings → Cloud save → Delete cloud save. No longer have the device? Make a transfer code on any device that still has the save (Settings → Cloud save → Move to another device) and enter it here. The save, its Google link and its open codes are deleted at once. Progress kept on a device stays there until you clear it.
Advertising and cookies
There are no ads on this site right now. The Google AdSense code is switched off and does not load, so no ad network sets or reads cookies here. The one cookie a visitor can get is set when you pick a language from the menu: it remembers that language for a year so the home page opens in it. Two more exist only in the browsers of the people who run the site. The Android app is different: now and then, between levels and never during play, it shows a full-screen ad from Google AdMob. Google may use your device’s advertising ID for it, or, where the law asks for your consent, only once you give it — Settings → Privacy choices lets you change that. Players under 13 get only non-personalised, child-safe ads.
What the server counts
Every page this site serves is counted: which page, in which language, and roughly which country — from a country code our hosting may attach to the request, or else your browser’s language setting, never looked up from your address. On the chess pages we also count which usernames get looked up. To estimate how many separate people that was, your address is cut back to its first three parts, mixed with your browser’s identifying string and a secret key that changes every day, week and month, and folded into a summary that cannot answer a question about any individual. Nothing is stored on your device for this, and no identifier outlives its day, week or month. If another site sent you here, we count its name — Google, Reddit — never the page or the search. Day-by-day counts are kept for fourteen days.
Logs
Each request leaves one line in the server log: the page asked for, the response code and a shortened network address with its last part removed. No browser string, no referring page, no cookies. Those lines are not fed into the counts above. To stop floods, the server also keeps the times of recent requests per address in memory — never written down, and gone at the next restart.
Third parties
Your browser talks to nobody but us. The game, its music, the typeface and every image come from our own server, and there are no third-party analytics, tag managers, social widgets or ad scripts. When you look up a chess player, our server — not your browser — asks Chess.com or Lichess for that public profile. The site is hosted on Render.