Privacy Policy

Who we are

Brain Stretch is made by the Brain Stretch team. For anything about your data, write to privacy@brainstretch.app.

What we collect, and why

• Play data. Your scores, levels, streaks, Mastery progress, badges and achievements, and the settings you choose. On your device this lets the app work; on our servers (in the guest account the app makes when your first session ends, or earlier, as soon as you open a friend's "Beat my run" link or a friend's Brain Card from an earlier day (on the website, once you tap to open it); or in the account you sign in with) it keeps your progress across phones and makes leaderboards, challenges and tournaments fair.
• Your first rounds and your streak. We keep the first timed round you play in each game (its score, level and date) so a later feature can show you how far you have come. We also keep your streak settings (the five-day week and any pauses) and your streak numbers (the streak your phone reports and the one our servers work out from your rounds), so every device you play on shows the same streak. Only you see these; friends see just your streak, as described below, unless you hide it. They are in the copy of your data you can ask us for, and they are deleted with your account.
• Monthly medals and trophies. Each month we count the days you play (the days our servers count toward your streak) against a goal set from the month before, and reaching it earns that month's medal. We keep each month's goal, your play-day count and the medal (its month, goal and days) for as long as you keep your account; friends see your medal row, as they see your streak. On the first of each month the app offers you a "My month" card: a calendar of the days you played the month before, with your medal if you earned one. The "My month" card is yours: nobody else sees it, and it leaves your phone only if you share it yourself, which players under 13 cannot. When you finish in the top places of a Friend Tournament with enough players, you earn a trophy, and we keep the place, how many played and the date. Every such tournament gives one: the house cup, or a design its host chose if the host has Pro. Trophies and medals are earned by playing, never bought. They are in the copy of your data you can ask us for, and they are deleted with your account.
• Round logs. The app sends the record of your taps and their timing for a round (its replay) to our servers, which replay it to verify the score: every Daily Test round (its Calm version too), every timed practice round with at least one right answer (not a replay of the same puzzle, a twist or a puzzle link), and every Daily Challenge, Friend Tournament and "Beat my run" round. Calm practice, the first-session Snapshot, Party, Pressure and Daily archive replays stay on your device. These logs hold no text you typed and no personal details. A Daily Test or practice log is not kept once it is checked, unless the check flags it; Daily Challenge, tournament and "Beat my run" logs are kept so results can be checked again (see How long we keep things).
• Account details. You start as a guest: when your first session ends, or earlier, as soon as you open a friend's "Beat my run" link or a friend's Brain Card from an earlier day (on the website, once you tap to open it), the app makes a guest account with a random player id, no name or email address. If you sign in with Apple or Google we receive an identifier and, if you allow it, your email address, so you can recover your account. We never see your password.
• Display name and friend code. A name you choose (use a nickname, not your real name) and a code you can give to people you want as friends: as the code itself, as a friend link (brainstretch.app/f/ followed by the code) or as a QR code of that link. The link and the QR code carry only your code, never your name. If you told us you are 13 or over, the page the link opens shows your public profile to whoever opens it, signed in or not: your display name and avatar (with the frame you chose), your country (if you joined a country board), the month you joined, your title, how many badges you have and three of them. Turn it off with Let players on public boards open my profile, and the page shows only the code; for players under 13, or who have not told us their age, it always shows only the code. Apart from what you give out, only you see your code in the app. The app reads your clipboard only when you tap Paste under Add a friend. If you install the Android app from a friend's link, Google Play hands their code, and what they shared (such as a medal), to the app, which offers to add them after your first session; nothing is sent until you tap. Who sees your display name:
  • Friends see your display name and avatar, your streak (unless you hide it), your levels, your Daily Challenge scores on friends boards, and your country if you joined a country board. On your player profile they also see your badges, the achievements you have unlocked, how many tournaments you have shared, and your head-to-head record with them over the last 30 days (the days you both played the Daily Challenge's free tries, and who holds the belt). Your rivals list shows who leads your head-to-head with each friend over the last 30 days, counting free tries only, and the day the lead last changed. Friends under 13 or who have not told us their age are not on it, and if that is you, you are not on your friends' lists either; between two friends who are 13 or over, each sees the same for the two of you, and nobody else does. Friends also see your monthly medals, in a row on your profile. On your friends board, the face with the most play days this month wears a small laurel (the consistency laurel): it uses the play-day counts friends already see, ties share it, and a hidden streak keeps you out of it.
  • Public boards and country boards: if you told us you are 13 or over, anyone, including people who are not signed in, can see your display name, your avatar (with the frame you chose) and Daily Challenge scores on the everyone board, and on your country's board (with your country) if you joined it. It is on by default. Turn it off with Show me on public boards in You → Friends and boards → Board profile; your friends still see you on friends boards.
  • Friend Tournaments: the host and everyone in a tournament you join see your display name and your scores in it, whether or not they are your friends (anyone with the invite link can join). If you host one, anyone with its invite link sees your display name as the host, without signing in, and the tournament's name, which carries your display name unless you chose a name of your own, goes with the trophies its winners keep, wherever their trophies show. If you win a week of a weekly tournament, your display name is engraved on its cup, which everyone in its later weeks sees, under the same rules as its board: players under 13, or who have not told us their age, appear as "A player" to anyone who is not their friend. Results a player shares from a tournament carry the top three's totals and the names of those among them who told us they are 13 or over; anyone else reads "A player", even when the player sharing is their friend, and in results you share, your own name appears only if you told us you are 13 or over. Your three chosen badges (or your top three, your showcase) show beside your name to the other players in a tournament, on its board and in its lobby, under the same rules as your profile: nothing for players under 13 or who have not told us their age, nothing to players who are not your friends when your profile is private (Let players on public boards open my profile turned off), and nothing either way when a block stands between you. A tournament's invite page: when you join a tournament, anyone who opens its invite link, without signing in, sees who is in; your avatar, display name and chosen badges show there only if you told us you are 13 or over and your profile is public (Let players on public boards open my profile on), otherwise you appear as "A player", and a block either way hides you from that person.
  • Challenge links ("Beat my run"): anyone with the link sees your display name, your score and your run, and your avatar only if it is one of the plain disc avatars: if your avatar is a face, the link carries no avatar and they see a plain disc made from your name (links made before version 1.4.1 of the app could carry a face). A link from a player under 13, or one who has not told us their age, carries no avatar.
  • Shared Brain Cards: anyone with the link sees your display name and avatar only if you leave Show my name on (below). A card is deleted 90 days after you share it.
  • Honours you share: when you share an honour from its celebration (a badge, a medal, a trophy), the picture carries that honour, your avatar and your display name. Only you decide to share it, and only if you told us you are 13 or over: players under 13, or who have not told us their age, have no Share.
  • Weekly recap: a weekly recap you choose to share, a picture made on your phone from your friends boards (text on the web), can carry the first word of a friend's display name and their avatar. Which names may leave your friends boards on a recap follows the age rule: only friends who have told us they are 13 or over, never players under 13 or who have not told us their age. The Show me on public boards switch controls public boards only: your friends still see your name on their friends boards and on a recap they share. The recap's Show friends' names switch leaves every name out; it carries no codes, ids or friends' scores, and we do not keep it.
  • Player profiles: tapping a player's name opens their profile. Your friends see the fuller profile above. If you told us you are 13 or over, a player who is not your friend and reaches you from a public or country board, a tournament, a friend request or your friend link can open a lighter one: your display name and avatar, your country (if you joined a country board), your title, how many badges you have and three of them, and your ranks on the boards; never your achievements, streak, days played, best Daily Challenge score or tournament record. It is on by default. Turn it off with Let players on public boards open my profile; it does not take you off the boards, and your friends still see your profile. Badges are awarded by our servers from the rounds they checked. Your title (your best world's, or another world title you hold) and the avatar frame you pick are earned with badges, never sold; your chosen title and frame show where your face shows: to friends, and to anyone who can open your profile. A player under 13, or who has not told us their age, is the only one who sees theirs. A trophy on your profile carries the name of the tournament it came from, written by its host and filtered (a host who deletes their account or is under 13 takes the name with them, and the trophy keeps a house name); hosts write nothing else that appears on your profile. A medal or a trophy can take one of the three places you choose to show, under the same rules as your badges. The achievements you unlock are copied to our servers (which ones and when) so your friends can see them; nobody else does. Players under 13, and players who have not told us their age, have no profile anyone else can open, friends included.
  • Players under 13 never appear by name to anyone who is not their friend: not on public or country boards, tournament boards or invite links, challenge links, Brain Cards, results they share, a weekly recap a friend shares or a player profile.
  Nobody else sees your account, your email address or your player id.
• Shared Brain Cards. When you share your Brain Card, we keep the card so the link can show it: the day's result as the card shows it (Sharpness, the worlds you played, your streak and personal bests, your Daily Challenge score) and, if you leave Show my name on, your display name and avatar. Anyone with the link can see the card, but never your account or player id. We never show a name for players who tell us they are under 13 or have not told us their age. A card is deleted 90 days after you share it, or with your account.
• Friends: the inbox, challenges, cheers and invites (from 18 November 2026). The Friends tab's inbox ("Waiting for you") shows what a friend did for you: a friend request, a challenge to beat their run or a rematch, the result when a friend played a challenge you sent (both scores), a cheer, or an invite to a Friend Tournament. Each shows the friend's display name, avatar and frame under the rules above, so a request from a player under 13, or who has not told us their age, shows no name; the inbox lists nothing about a player who did not do something for you. Only friends can challenge, cheer or invite you, and a challenge sent to a friend shows in their inbox alone (the link you can share stays as it is). Cheers are preset lines only, at most one a day between two friends, with nothing attached. We keep cheers and invites for 30 days; an item leaves the inbox when what it points to does (a challenge when it expires, an invite when the tournament closes, a cheer or a result after 7 days). The inbox also shows Spark, the app's coach: a run to race each day, a rematch after you race it and a cheer after your first Daily Test, labelled "Coach, not a player". Spark is not a person and never sends notifications. All of it is deleted with your account.
• Friend notifications (from 18 November 2026). You can switch on notifications for when a friend does something for you: a friend request, a request accepted, a challenge or rematch, a tournament invite, a cheer, or the result of a challenge you sent. They are off until you switch them on on the Friends tab; only then does the app ask your phone for a push token (an address for Brain Stretch on that device) and send it to our servers with your time zone and the app's language. Each notification is a preset line with the friend's display name, under the same rules as the inbox; a friend request's notification carries no name and no face ("You have a new friend request"). Players under 13, or who have not told us their age, get friend notifications only if they switch them on, and only from friends. We send none between 21:00 and 08:00 your time, none from an account less than a day old and none while you take a break, and only a few a day: one back-and-forth a day with each friend, and at most three a day that friends start. To keep to those limits we keep a count per pair of friends per day and the queue of notifications to send, for 30 days. The push token is kept while friend notifications are on, and deleted when you switch them off or 90 days after the last notification sent to it. The web version gets no notifications, only the inbox. All of it is deleted with your account.
• Purchases. Which products you bought and when, so Pro and Ad-free work on every device you sign into. Payment itself is handled by Apple, Google or the web store; we never see card numbers.
• Usage data. Which screens and games are used, how rounds end (the score, never your answers), and the kind of link that first brought you to the app (a medal, a trophy, a friend's invite; never who sent it), so we can improve the app. It is tied to a random id made on your phone for this purpose, never to your account, name or email address, and we never collect it from players who tell us they are under 13. You can turn it off in the app (see Your choices).
• Crash reports. When the app crashes or a screen fails: what went wrong and the screens open just before it, the app version, and the phone model and system version, so we can fix the problem. Crash reports carry no name, email address or player id.
• Your age band. We ask whether you are under 13, 13 to 17, or 18 or over. The answer is kept on your device and stored with your player account on our servers, so ads stay age-appropriate (or never start) and players under 13 stay off public leaderboards. It is deleted with your account.

Ads

The free version shows ads between rounds, never during a round, and an optional rewarded ad you can choose to watch. Ads are served by Google AdMob.

• Under 13: no ads at all; the ad software is never started.
• 13 to 17: only non-personalised, general-audience ads.
• 18 and over: personalised ads only where you have agreed to that in the consent prompt. You can change your choice at any time on the You tab under Your data → Ad privacy choices, and in the EU, UK and US states with privacy laws we show the choice before any personalised ad.
• On iPhone and iPad: players 13 and over are asked once by iOS whether Brain Stretch may track them for ads, before the consent prompt and before any ad loads. Ads are personalised only if you allow it there (and, for 18 and over, in the consent prompt); only then does AdMob receive your device's advertising identifier. You can change it at any time in Settings → Brain Stretch → Allow Tracking, which the You tab's Your data → Tracking for ads opens.

AdMob may work out an approximate location from your IP address to serve ads. We do not ask for location permission, and the app never reads your precise location.

Buying Ad-free or Pro removes ads entirely.

If you report an ad from the app, we keep the report: the reason, any note you add, which ad it was (the ad unit and AdMob's reference for that ad), the app version and platform, and your player id. We use it only to look into the ad, and it is deleted with your account.

Services we rely on

Your data is processed by companies acting on our instructions:

• Supabase stores accounts and play data in the European Union (Ireland).
• Microsoft Azure runs our servers in the European Union (Ireland) and hosts the web version.
• RevenueCat keeps the record of purchases.
• Google AdMob serves ads, under the choices described above.
• PostHog receives usage data (which screens and games are used, under a random id that is not your account), on servers in the United States, and only from players aged 13 and over who have not turned it off.
• Sentry receives crash reports (the error, the app version, and the phone model and system version), on servers in the United States, with no name, email address or player id.
• Expo (from 18 November 2026) runs the push service that carries friend notifications: it receives each device's push token and the notification's preset line, on servers in the United States, and passes them to Apple or Google to deliver.
• Apple and Google handle sign-in, payments and the app stores under their own policies.

How long we keep things

• Account and play data: until you delete your account.
• Friend challenge links ("Beat my run"): the run and its link expire three days after they are made.
• Shared Brain Cards: deleted 90 days after they are shared.
• Round logs: a Daily Test or practice log is not kept once it is checked; Daily Challenge, tournament and "Beat my run" logs are kept up to 180 days, and the log of a round the check flags up to two years.
• Tournament data: kept with the tournament's results for the players in it; your placings and badges stay with your account.
• Reports about a player: kept with the outcome of the review until your account or theirs is deleted.
• Friends (from 18 November 2026): cheers, tournament invites, the queue of friend notifications and the count per pair of friends for 30 days; a push token until you switch friend notifications off, or 90 days after the last notification sent to it.
• Usage and crash data: up to two years, then deleted.

Your choices

• Delete your account from You → Your account → Delete account (shown once you are signed in). This removes your account and everything it holds on our servers.
• Delete all local data from You → Your data → Delete all local data to wipe the app's data on that device.
• Usage data and crash reports: turn off You → Your data → Share usage data and that phone stops sending both.
• Ad choices in You → Your data → Ad privacy choices (shown where a choice applies), and in your phone's own ad settings.
• Public boards: turn off You → Friends and boards → Board profile → Show me on public boards to leave the everyone and country boards. Players under 13 are never on them.
• Player profile: turn off Let players on public boards open my profile so that only your friends can open it and your friend link's page shows only your code; you stay on the boards. You choose which three badges others see first.
• New friend code: get a new code from your profile if yours has spread further than you meant; the old code, its links and its QR code stop working.
• Block a player from your Friends list, from their profile (opened from any board, or from their board row when their profile is closed) or from a tournament's board. They are not told; they can no longer send you requests, open your profile or join tournaments you host.
• Report a player from their profile (or from their board row when their profile is closed), for their name, their avatar or something else, with a short note if you like. We keep the report with your player id, and the reported player's display name and avatar as they were, so it can be acted on; we review every report within a week. The player is not told who reported them, and the report is deleted with your account or theirs.
• Friend notifications (from 18 November 2026): off until you switch them on on the Friends tab; switch each kind (requests, challenges, invites, cheers) on or off under Reminders; mute a friend from one of their notifications or from their profile (they are not told, and what they do still reaches your inbox). Turning Reminders off or taking a break stops them all.
• Hide a friend or report a shared link from the link itself.
• Ask us for a copy of your data, a correction, or deletion at privacy@brainstretch.app. If you are in the EU or UK you also have the right to complain to your data protection authority.

Children

Brain Stretch is a game for everyone, and we treat players who tell us they are under 13 with extra care: no ads, no personalised advertising, no sign-in prompts, no public or country boards, no profile anyone but themselves can open, and never their name shown to anyone who is not their friend. We do not knowingly collect personal information from children beyond what the game needs to run. From 18 November 2026 they get friend notifications only if they switch them on, and only from friends, and a friend request from them shows no name in anyone's inbox. If you believe a child has given us personal information, write to us and we will delete it.

Scores are not medical information

Scores and levels in Brain Stretch reflect performance in this app's games. They are not a medical, clinical or IQ assessment, and we do not use them to draw conclusions about your health.

Changes

If this policy changes in a way that matters to you, the app will tell you before the change takes effect, with a short note on its Today screen, and we post the new version here ahead of the date, 14 days where the change touches what we collect; the 4 November version was posted on 1 November, three days ahead: its lines describe what you can show to others, and the one new item of usage data in it, the kind of link that first brought you to the app, is a kind, never a person. The date at the top is the date this version takes effect.

• 18 November 2026: the lines on the Friends inbox, challenges sent to a friend, cheers, tournament invites, friend notifications and their push token, and Expo's push service take effect. Until then the version of 4 November 2026 applies: this page without those lines, and nothing they describe is collected before that date.
• 4 November 2026: the lines on monthly medals and the "My month" card, the consistency laurel on friends boards, your avatar and frame on public boards, your showcase in tournaments, trophies and the engraved cup of a weekly tournament, the picture you share with an honour and who is in on a tournament's invite page take effect. Until then the version of 31 October 2026 applies, with the 1 November change below: this page without those lines.
• 1 November 2026: a "Beat my run" link carries your avatar only if it is a plain disc, never a face. It shares less than before, so it applies now, from version 1.4.1 of the app.
• 31 October 2026: what we keep of your first rounds and your streak, seen by you alone.