Privacy policy
Private test version. Last updated 15 November 2026. Before public release the operator's name and postal address will replace the placeholders below.
The short version (for everyone, written for players aged 13 and up)
- You can play without an account. Then your settings and saved games stay on your device.
- If you play online, our server sees the nickname you choose, your moves and your clock times. Other players see your nickname, avatar and rating.
- If you make an account we do not ask for your name, email, phone number or password. The app makes a secret key that stays on your device and a recovery code that you write down.
- We ask your year of birth once to check you are 13 or older (and, only if the year is not enough to tell, the month). We do not keep it.
- Nobody sees you in "Players online" unless you switch on "Show me as online", and nobody can challenge you unless you switch on "Accept challenges". You can block any player.
- The game never connects to our server before the age check. After it, the game asks our server once, when it starts, whether online play is open in your country; everything else is sent only when you choose something online, such as "Players online" or "Play online".
- No adverts, no tracking, no selling your data.
- To stop cheating we look at how long each move took, your results, and how often the game was in the background while it was your move. This can raise a flag for a person to look at. A person, never a computer on its own, decides if someone broke the rules, tells you why, and you can appeal.
- You can delete your account in the app at any time (Account tab, then Delete account). You can ask us what we hold about you, or ask us to fix or delete it: [email protected].
- If something worries you, talk to a parent, carer or teacher, and see Safety & reporting.
1. Who is responsible for your data
ChesStresS is run by Kajetan Kupka, a private individual in the United Kingdom (not a company), [POSTAL ADDRESS] ("we", "us"). We are the controller of the personal data described here. ICO registration number: [ICO REGISTRATION NUMBER].
Contact for privacy questions, requests and complaints: [email protected] (write "Privacy" in the subject). We do not have a data protection officer; the operator handles privacy matters personally. Emails are drafted with the help of an AI assistant (see section 6); every decision about your data, a ban, a refund or a complaint is made by a person.
The UK GDPR and the Data Protection Act 2018 apply. If you live in the European Union, the EU GDPR also applies to you. [EU REPRESENTATIVE: name and address, if appointed – see section 9.]
2. What we collect and where it is kept
On your device only (not sent to us)
Your settings (board, sound, theme, time control), your level, local tokens and ratings when you play as a guest, games against the computer, saved games, puzzle and lesson progress, game-analysis results, a flag that you passed the age check, and – if you have an account – your account number, secret key and nickname. These are kept in your browser's or app's local storage. They stay until you delete the app or clear the site's data.
When you play online (guest or account)
- Identity in the game: a random player number created by the app (guests) or your account number, and the nickname you type (guests) or your account nickname. Nicknames can use Latin letters only (with accents), digits, spaces and the signs _ . - and are checked by a word filter and against names already taken (a look-alike of a taken name is refused; a guest who types one is shown as “Guest-xxxx”).
- Connection: the game never connects to our server before you have passed the age check. After that it asks the server once, each time it starts, whether online play is open in your country (see “Technical data” below; nothing about you is stored). Everything else is sent only after you choose an online feature in this session (opening "Players online", Play online, Challenge a friend, or the Online, Tournaments, Turbo Live, Watch, Four Stressed or Wild Stressed online screens). The page Safety & reporting asks the server for its transparency numbers when you open it.
- Presence: only if you switch on "Show me as online" (off unless you switch it on; Settings, or the switch in the "Players online" card): your nickname, avatar, rating (accounts: CSR, and TSR if you have played rated Turbo Live), whether you accept challenges and whether you are playing are shown in the "Players online" list to other connected players. Accounts are listed while connected; guests only while they are on the home or Online screen or looking for a game. "Accept challenges" is also off unless you switch it on.
- Block list: the players you block. For accounts it is kept on the server with the account (the blocked player's account or guest number and the nickname you saw); for guests it is kept only on the device. Blocked players are not told.
- Games: the moves, the result, the time control, your clock times and the time you took for each move.
- Focus signal: in online games the app counts how many times, and for how long in total, the game's tab or app was hidden (in the background) while it was your move. It sends only those two numbers per game. It never reads, records or sends what you were doing, which other apps or pages were open, your screen, or anything you typed. Switching away is not against the rules and the numbers can be wrong, so they are treated as weak, unverified evidence that only a person weighs (see “Fair play and reports”).
- Preset chat and reactions: which of the fixed phrases (such as "Good game") or, at a four-player table, which of the fixed reactions you sent. You cannot type your own messages.
- Four Stressed and Wild Stressed tables (chess for four, and Wild Stressed for two or four): you can make a table for friends (a code or link) or join a quick table, where you meet players you do not know; other people can watch a table. While an online table exists, the server keeps its 5-letter code, the nickname, avatar and seat of each player, their account number or device identifier (so that a player who reconnects gets the seat back), the moves and the scores. Nothing from these games is saved on your account, and there are no ratings or tokens. The players at the table and people watching see your nickname, avatar, moves, score and reactions. You can report or block a player at the table; the report is kept as described under “Fair play and reports”. A table is deleted 2 hours after its game ends, 2 hours after the last move of a game nobody finished, or after 30 minutes with nobody connected before the game starts.
- Tournaments and Turbo Live: that you joined, your results, points and standings (in Swiss tournaments also your rating at entry, your opponents and colours in each round, and tie-break scores), and token entry fees, refunds, prizes (tournaments only) and top-ups. In Turbo Live also how many votes you cast, how many matched your team's move and your teams' results, which are used to calculate your TSR when a rated event ends.
- Technical data: your IP address and basic connection information are processed by our hosting provider, Cloudflare, to deliver the service and protect it from attacks. We do not store IP addresses in our own game database. Online play is open only in some countries (at present the United Kingdom, Australia, New Zealand and Poland): Cloudflare tells the server which country a connection comes from, worked out from the IP address, and the server uses it only to allow or refuse starting online play. The country is not stored.
- Network identifier (accounts only): when an account is created or connects to the lobby, the server turns the IP address together with the browser family and operating-system family (for example “Chrome on Android”) into a scrambled code using a secret key (a salted hash) and stores only that code with the account number, for at most 30 days after it was last seen. The code cannot be turned back into an IP address. It is used for one thing: noticing when several accounts appear to come from the same device or network, which may point to one person using several accounts. People in one home, school or club share a code, so a match proves nothing on its own; a reviewer sees it only as “possible same device/network”, never the code or an IP address.
- When you create an account: the server records that you confirmed you are 13 or older, which version of the Terms you accepted, and when. To stop accounts being created in bulk, it counts new accounts per network for 24 hours using a scrambled form of the network address (not the address itself). After an account is deleted or closed, a scrambled form of its nickname is kept for 90 days so that nobody else can take the name straight away. In a game against the computer played with an account, a win is paid only after the server has replayed the moves of that game; the moves are not kept after the check.
If you create an account
- Account number, nickname, the date you joined, the date you last used the account, a scrambled (hashed) copy of your secret key and recovery code (we cannot read the originals), your ratings (CSR for each speed, and TSR for Turbo Live: rating, deviation, volatility, number of games or events, date of the last one), your Turbo Live badges (for example “Marathon Top 10 — week 46, 2026”, with the date), level and experience points, token balance (split into earned and bought tokens), the last 200 token changes (the token history, each change marked earned or bought), when you last claimed free tokens, the boards and premium avatars you bought with tokens, your avatar choice, your "accept challenges" and "show me as online" settings, and your block list.
- For games against the computer: a single-use ticket per game (room, fee, the result you reported, what was paid and when), so that a prize is paid only once and the daily limit on winnings can be applied. Tickets older than 7 days are deleted when you start your next game.
- Turbo practice is free and runs only on your device: we no longer store any Turbo practice tickets. Tickets kept from when practice used tokens are deleted once they are 7 days old, or with the account.
- Your spending controls: monthly spending limit, a pending change to it, and a purchase pause.
- To be able to delete every copy when you delete the account, a list of the game rooms, tournaments and Turbo Live events you took part in (kept only while those copies exist).
- Your last online games (players' nicknames, moves, result, time control, date) so you can see them in the Account tab.
- Your public profile – nickname, level, ratings (CSR and TSR), up to 20 most recent badges, number of games, avatar and whether you accept challenges – can be looked up by nickname by anyone using the game. Your CSR and TSR appear on the leaderboards once established, and your name, points and TSR in Turbo Live standings and the Weekly Marathon ladder. How ratings are calculated: How ratings work.
We do not collect your real name, email address, phone number, password, contacts, photos, precise or approximate location, or advertising identifiers.
Fair play and reports
- For every finished online game we keep a fair-play record: the players' numbers and nicknames, the result, time control, ratings before the game, the moves, the time taken for each move, simple facts about each position that need no chess engine (how many legal moves there were, whether the move was a capture, a check or a recapture), timing statistics worked out from these (average, spread, how even the times were, time on forced moves compared with quiet moves), the focus signal described above, and whether the game ended by a player leaving or letting the clock run out in a lost position.
- Signals and flags (profiling for fair play). For each account the server keeps, for 30 days, a short line per finished game (opponent, result, expected result from the ratings, and which of the signals above the game showed). From these it works out whether an account meets one of the published thresholds, for example very even move times in many games, results far above its rating, many one-sided games between the same two accounts, a run of very quick losses, repeated quick draws between the same players in tournaments, repeatedly abandoned games, or several accounts on one network identifier. If it does, a flag is put in a queue for a person. A flag changes nothing for you: it does not restrict, label or slow down your account, and it is not shown to other players. The thresholds are published in our Online Safety records and summarised in Safety & reporting. Flags are sometimes wrong; that is why a person decides.
- No chess engine analyses your games on our server. When a person reviews a case they may run an engine on a game on their own computer.
- If you report a player we keep the game or the place where you met the player (Players online, a tournament, a Turbo Live event or a four-player table), the category you chose, the nickname you saw, your optional note (at most 300 characters), and later the reviewer's decision and note.
- Decisions. If a person decides to take action about you (a warning, a restriction on rated play, on tournaments and Turbo Live or on chat, a forced change of nickname, or closing the account), we keep the decision: what was decided, the reason category, the explanation written for you, how long it lasts, and the status of any appeal. You see it in the app (Account tab, "Notices") with the date and how to appeal. The player who reported you is told only that the report was reviewed.
- Rating corrections. If an account is closed or marked for cheating, opponents who lost rating points to it in rated games in the previous 90 days get those points back. We keep a record of each correction (your account, the game, the category and the number of points) and show you a notice. If the decision is overturned on appeal, the corrections are reversed and you are told.
- Leaving games. We keep, for up to 3 days, a note of live games you lost on time while disconnected. It is used only for the game rule that pauses rated pairing for 10 minutes after three such games in 24 hours (Terms, section 7).
- Audit log. Every action the operator takes in the review tool (recording a decision, closing a report or flag, an appeal step, a nickname scan) is written to a log that cannot be edited. It contains the time, the action and the reference number of the decision, report or flag; it does not contain your nickname or account number.
When you email us
Your email address, your name if your email shows it, what you write, and any attachments.
Purchases (not available yet)
Nothing can be bought yet: on the website the "Get tokens" screen shows the planned token packs and prices, and its Buy buttons read "Coming soon"; in the apps from the App Store and Google Play no packs, memberships or prices are shown until they can be bought there. When tokens can be bought, payment will go only through Apple's App Store or Google Play. For each purchase we will keep: the account it belongs to, the store's transaction number, the product (number of tokens), the price in pounds, the date and time, and the time you confirmed that you want the tokens at once and lose your 14-day right to cancel. We will never receive your card details. This policy will be updated before purchases go live.
3. Why we use it and our legal basis
| Purpose | Data | Legal basis (UK GDPR Article 6) |
|---|
| Running the game you choose: online games, pairing, ratings, accounts, tokens, tournaments, Turbo Live, saved game lists | Game identity, presence, games, account data, token history | Contract – providing the service you asked for (6(1)(b)). Where a contract does not fit (for example for guests), our legitimate interest in running the game you started (6(1)(f)). |
| Fair play and conduct: detecting signs of cheating, boosting, sandbagging, collusion, multiple accounts, stalling and abandoning games (signals and flags); checking reports; deciding on warnings, restrictions and closures; correcting ratings; applying the leaving-games rule | Fair-play records, signals and flags, focus signal, network identifier, reports, decisions, rating corrections, audit log | Legitimate interests – fair games and a safe, respectful place for all players, including children (6(1)(f)). This is profiling to prevent cheating and abuse. It never decides anything: every measure against a player is decided by a person, shown to the player with reasons, and can be appealed. The leaving-games pause is a fixed game rule applied the same way to everyone, lasts 10 minutes and affects rated pairing only. |
| Keeping players safe and dealing with illegal content and complaints, as the Online Safety Act 2023 requires | Reports, nicknames, related games, emails | Legal obligation (6(1)(c)) and legitimate interests (6(1)(f)) |
| Security and preventing abuse of the servers | Technical data processed by Cloudflare | Legitimate interests (6(1)(f)) |
| Answering your emails and requests | Emails | Legitimate interests (6(1)(f)); legal obligation for data-protection requests (6(1)(c)) |
| Purchases and refunds (when available); keeping accounting records | Transaction records | Contract (6(1)(b)); legal obligation for tax records (6(1)(c)) |
We do not use your data for advertising, we do not build profiles for marketing, and we do not sell or rent it. We do not make decisions about you by automated means alone: the fair-play signals only put a flag in front of a person, and warnings, restrictions and closures are always a person's decision (so Article 22 UK GDPR, on solely automated decisions, does not apply). You can object to processing based on legitimate interests (section 8), ask a person to look at a decision again (appeal), and ask what signals and flags we hold about your account.
4. Storage on your device (cookies and similar)
We do not use cookies. The game uses your browser's or app's local storage for the items listed in section 2, plus one session flag so the intro is shown only once per visit. This storage is needed for the game to work as you asked (saving your settings, games and account key) and is never used for tracking or advertising, so no consent banner is needed. You can delete it at any time by clearing the site's data or uninstalling the app – but if you have an account, write down your recovery code first, or you will lose access.
5. How long we keep it
| Data | How long |
|---|
| Data on your device | Until you delete it or the app |
| Account record, ratings (CSR, TSR), badges, tokens, boards bought, avatar, settings, spending controls, block list | Until you delete the account, or until it has not been used for 24 months: then it is deleted automatically, in the same way as when you delete it yourself. If you open the game in the last 30 days before that, you see a notice and the account is kept. An account that still holds bought tokens is not deleted for not being used (bought tokens do not expire); it is kept until you delete it or the bought tokens are spent. |
| Tickets for games against the computer | At least 7 days: tickets older than that are deleted when you start your next game; all are deleted with the account |
| Old Turbo practice tickets (no new ones are stored) | Deleted once they are 7 days old, and with the account |
| Token history | The last 200 changes per account; all deleted with the account |
| Your games in account histories | While your or your opponent's account exists. If you delete your account, your nickname in these games becomes "Deleted player"; a game is deleted when neither player has an account any more. |
| Fair-play record of a game (including moves, time per move and the focus signal) | 30 days after the game, unless the game was reported or is part of a flag |
| Per-account signals (one line per game) | 30 days after the game |
| Confirmation that you are 13 or older, the version of the Terms you accepted and the time | With the account, until it is deleted |
| Count of new accounts per network (a keyed hash of the network address, not the address) | 24 hours |
| One-way hash of the nickname of a deleted or closed account (the nickname itself is not kept) | 90 days after the deletion or closure |
| Moves of a won game against the computer sent for the prize check | Not kept after the check |
| Network identifier (salted hash; accounts only) | At most 30 days after it was last seen; deleted with the account |
| Flags and the fair-play records of the games in them | An open flag nobody acted on: 90 days after it was last updated. A flag a person reviewed: 12 months after the review. Deleted with the account it is about. |
| Reports, the fair-play record of a reported game and the decision | Until reviewed, then 12 months after the decision (deleted automatically) so that appeals and repeated reports can be handled |
| Decisions about an account (warning, restriction, forced rename, closure) and appeals | 12 months after the decision, or for as long as the measure is in force if that is longer. If you delete your account the decision is kept for the rest of that time without your account number or nickname. |
| A closed account | The account and its data are deleted 12 months after the closure (so that an appeal can be handled and the closure cannot be undone simply by waiting). An account closed because its owner is under 13 is deleted 7 days after the closure. You can delete it yourself at any time before that. |
| Rating corrections, rating history and the per-game rating change | Corrections and rating history: 12 months. The rating change of a game is kept with the game in the account history. |
| Results of a rated Turbo Live event used for TSR corrections (account ids, agreement, votes, team results, TSR before the event) | 90 days after the event, or until one of the accounts is deleted, whichever is sooner |
| Notes of abandoned live games (leaving-games rule) | Up to 3 days |
| Audit log of the operator's actions (no nickname or account number) | 6 years (the period in which legal claims can be brought), then deleted |
| Server copy of each online game (players' numbers and nicknames, moves, clocks, time per move) | 30 days after the game ends (correspondence games too: the 30 days start when the game ends), then deleted automatically. A challenge link nobody opened is deleted 30 days after it was made; a game without a clock in which nobody has moved for 180 days ends as abandoned. Games in account histories are kept as described above. |
| Players online list and pairing | While you are connected (and listed only as described in section 2); who was paired with whom is remembered for 10 minutes |
| Public lists of live and recent games | Live games until they end; the 50 most recent finished public games, replaced as new games finish |
| Tournament and Turbo Live results (nicknames, scores, payouts, TSR changes and badges shown in the standings) | Shown in lists for 1 hour after the end (Weekly Marathon: until the next week ends). The stored tournament or event is deleted 30 days after it ends (or 30 days after it was made, if it never started). Entry fees, refunds, prizes and top-ups stay in the token history of each account. |
| Technical data at Cloudflare | Not stored by us; Cloudflare keeps limited logs under its own policy |
| Support emails | 24 months after the last message, unless needed longer for a dispute or a legal claim |
| Purchase records and the record of your consent to immediate supply (when available) | 7 years after the purchase, then deleted automatically. This covers what tax law requires (at least 5 years after the 31 January tax-return deadline for the tax year) and the 6-year period for claims about a contract. If you delete your account, these records are kept for the rest of that period without your account number, nickname or anything else that links them to your account. |
| Year (and, if asked, month and day) of birth | Not stored at all; only the result of the check is kept on your device |
6. Who receives your data
- Other players see your nickname, avatar, rating, games, preset chat phrases, reactions and results. Public games (not private games with a friend) can be watched live by others and appear in "recent games" lists; games may be shown inside ChesStresS and on its official channels.
- Cloudflare, Inc. (USA) hosts the website and the game server (Cloudflare Pages, Workers and Durable Objects) as our processor, under Cloudflare's data processing addendum.
- Fonts: the game's fonts are part of the game and are loaded from our own site (or from inside the app). No font service, such as Google Fonts, receives your IP address.
- Google provides the support mailbox (Gmail). Under Google's consumer terms Google acts as a separate controller for the mailbox service. [If the mailbox is moved to Google Workspace, Google will act as our processor.]
- [AI SERVICE PROVIDER] processes the text of support emails when we use its AI assistant to help draft replies, as our processor. We do not send it your account key or recovery code.
- Apple and Google (when purchases are available) process payments, refunds and parental purchase approvals as independent controllers under their own privacy policies.
- Authorities, such as the police or Ofcom, only when the law requires it or to protect someone from serious harm.
7. Transfers outside the UK
Cloudflare and Google are based in the United States and process data in many countries. Both are certified under the UK Extension to the EU-US Data Privacy Framework (the "UK-US data bridge"), which UK law treats as giving adequate protection. Cloudflare's data processing addendum also includes standard contractual clauses with the UK addendum as a fallback. For EU players, the EU-US Data Privacy Framework and standard contractual clauses apply. You can ask us for more detail.
8. Your rights and how to use them
You have the right to: get a copy of your data; have wrong data corrected; have your data deleted; restrict or object to how we use it; and get the data you gave us in a reusable format. You will not be subject to decisions made only by a computer: fair-play flags are reviewed by a person, and you can appeal any decision (Safety & reporting).
- Delete your account yourself: in the app, Account tab, then "Delete account". See Delete your account for what is deleted and the email route.
- Everything else: email [email protected]. Tell us your nickname. Because we do not know your email address or real name, we check that the account is yours by asking you to make a small change in the app (for example, choose a particular avatar) and then looking at your public profile. Never send us your secret key or recovery code.
- We reply within one month. If your request is complex we may extend this by up to two more months and will tell you why. It is free.
- Guests have no account, so we can usually find their online data only if they tell us the nickname used and roughly when they played.
- If you are under 18 you can use these rights yourself. A parent or carer can help you or ask for you.
9. Complaints
Please tell us first if you are unhappy with how we use your data: email [email protected] with "Privacy complaint" in the subject. We confirm receipt within 30 days (usually within a few days), look into it, keep you updated and tell you the outcome.
You also have the right to complain to the UK Information Commissioner's Office (ICO): ico.org.uk/make-a-complaint, telephone 0303 123 1113. If you live in the EU you can complain to the data protection authority in your country.
9b. If you live in Poland
The EU General Data Protection Regulation (GDPR) applies to how we handle your data, and you have all the rights in section 8. The Polish version of this policy is the binding one for you. Contact for people who live in the European Union: write to us at [email protected]. We have not appointed a representative in the European Union yet. You can complain to the Polish data protection authority: Prezes Urzędu Ochrony Danych Osobowych (UODO), ul. Stawki 2, 00-193 Warszawa, uodo.gov.pl. Nothing is sold in Poland at present: the game is free there.
9a. If you live in Australia or New Zealand
New Zealand. The Privacy Act 2020 applies to how we handle your information. Our privacy officer is the operator named in section 1; write to the contact address in that section. You can ask us to confirm whether we hold information about you, to give you a copy and to correct it; we answer within 20 working days and do not charge. Your information is collected and kept outside New Zealand (section 6 and section 7 say where and by whom). If a privacy breach is likely to cause you serious harm, we will tell you and the Privacy Commissioner. If you are not happy with our answer you can complain to the Office of the Privacy Commissioner: privacy.org.nz, telephone 0800 803 909.
Australia. We are a small business based in the United Kingdom, so most of the Australian Privacy Act 1988 does not bind us; we still give Australian players the same rights as everyone else: everything in section 8 applies to you (access, correction, deletion, a copy of your data). Your information is kept outside Australia (sections 6 and 7). You can contact the Office of the Australian Information Commissioner at oaic.gov.au, telephone 1300 363 992. For online safety (bullying, image abuse, illegal content) you can also go to the eSafety Commissioner: esafety.gov.au/report.
10. Children
ChesStresS is for players aged 13 and over. We ask your year of birth once, on the device (and the month only if the year is not enough), and do not keep it; if you are under 13 the game will not start and does not connect to our server. Because some players are teenagers, we follow the ICO's Children's code: privacy-friendly settings ("Show me as online" and "Accept challenges" are off until you switch them on), a block button, no adverts, no tracking, no location, no open chat (only preset phrases and reactions), report and block wherever players meet, and a person reviews every report. If we learn that a child under 13 has an account (they tell us, a parent or carer tells us, or a report makes it clear), a person closes it the same day, online play is switched off on that device, and the account and its data are deleted 7 days later (the 7 days are only there so that a mistake can be put right). We do not ask for proof of age. Parents or carers who think their child under 13 has used the game can email us with the nickname.
11. Security
Connections are encrypted (HTTPS and secure WebSockets). Account keys and recovery codes are stored only as one-way hashes. Admin functions need a separate secret key. If a data breach puts you at high risk, we will tell you without undue delay through the app and our website.
12. Changes
We will update this policy before adding purchases, subscriptions, a server for game analysis, or any new kind of data use, and show a notice in the game when a change matters to you. The date at the top shows the latest version.
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