Privacy Policy

The controller within the meaning of the EU General Data Protection Regulation (GDPR) for the data processing described in this policy is:

• Klaus Greiner — Brainelo
• Gemündener Str. 28
• 13189 Berlin-Bezirk Pankow, Germany
• Email: klausgreinerdev@gmail.com

Questions about privacy, requests under your rights (see section 9) or complaints: write to the email address above — every request gets an answer.

This policy covers the marketing website brainelo.de, the browser game at play.brainelo.de and the Brainelo mobile app (called “Brain Elo” on Google Play and on your home screen) — together referred to as the “service”. Your use of Google services (sign-in, notifications, analytics) is additionally governed by Google’s own privacy policy.

brainelo.de is a fully static site. It sets no cookies, loads no external fonts or CDN resources, and uses no analytics or advertising — that is why you see no cookie banner: there is nothing to consent to.

Like virtually every website, the hosting provider of brainelo.de (Google Firebase Hosting) processes technical request data in so-called server logs — including IP address, time of access, requested page and browser user agent — in order to deliver the site, ensure its security and diagnose errors. The legal basis is our legitimate interest (Art. 6(1)(f) GDPR). Google keeps these logs only for a limited period. If you join the iPhone waitlist on the website, the form sends the email address you enter straight to our own API at api.brainelo.de (see section 6).

• Google Privacy Policy

To play, you create an account or start as a guest. We process:

• Account data: sign-in method (Sign in with Apple on iPhone and iPad, Google sign-in, email address with password, or an anonymous guest identifier), your email address (with Apple, Google or email sign-in; with Sign in with Apple you can share an Apple relay address instead of your own), username, display name and the look of your brain avatar (the items you dress it with; there are no profile pictures, and we don’t copy the photo of your Apple or Google account). A guest can later link Apple (on iPhone and iPad), Google or an email address and keep their progress as a permanent account. If you sign out of a guest profile, the app receives a one-time ticket that is valid for 30 days and that we store only as a SHA-256 hash; your next sign-in uses it to move the guest’s progress into that account, and the guest profile is then deleted.
• Profile and onboarding data: your birth year, if you enter it, from which we derive an age group (under 18, 18–29, 30–44, 45–59, 60+) to compare your results with players of your age; your answers to the onboarding questions (what brings you to brain training, where you notice mental fatigue first, how many minutes a day you want to train and which time of day suits you), which we use to choose your daily games; which of the two versions of the introduction you were shown and — if you start a Pro trial or subscription — the date of your first trial and of your first payment, which we use to compare the two versions (our legitimate interest in an introduction that works, Art. 6(1)(f) GDPR); your timezone (for daily challenges, streaks and reminders) and your app language.
• Gameplay data: game results, Elo ratings, XP, streaks, daily-challenge progress, achievements and your weekly league group and placement.
• Social data: friends and friend requests, the challenges you send or receive, the challenge and invite links you create and — if you use the family plan — the family you belong to; the players you block and the reports you send (a report keeps the reported player’s name as you saw it, and we never tell that player who reported them).
• Support and feedback: support requests and the files you attach to them, and the suggestions and votes you submit.
• Technical data: sign-in credentials and session tokens (managed by Firebase Authentication, Google), the app version and a device identifier that the app sends with every request to our API. It stays the same when you reinstall the app: on Android it is a SHA-256 hash of the identifier Android assigns to our app (Android ID), on iPhone and iPad a random identifier kept in the device’s keychain, and in the browser a random identifier in the browser’s storage. The app also stores your settings, your sign-in session and your consent choices on your device; this is strictly necessary to provide the app (§ 25(2) no. 2 TDDDG).
• Visible to other players: your username, display name, brain avatar, Elo ratings, XP, league, streak and when you last played; signed-in players can also see your achievements. This appears in leaderboards, player search, profiles, weekly leagues and challenges. A league group has up to 12 players, who see each other’s weekly XP. Your birth year and age group are never shown to other players.
• Friends: your friends list, and the streaks and recent games of you and your friends, are visible to other signed-in players on your profile. Profiles, player search and leaderboards can also be seen without signing in.
• Challenge links: anyone who opens a challenge link you share — and the link preview that chat apps show for it — sees your name, the game and your score.
• Family plan: the owner and the members of a family see each other’s names and brain avatars, and in the family league each other’s weekly XP, league and won weeks. Anyone who opens a family invite link sees the owner’s name and brain avatar and how many places are taken.

This data is stored on our servers at Hetzner Online GmbH in Nuremberg, Germany (see section 7). It is used to provide the game, your ratings, leaderboards, leagues and social features. Legal basis: performance of the (free) usage contract, Art. 6(1)(b) GDPR; security and abuse prevention: Art. 6(1)(f) GDPR.

Name checks: display names are public, so every new display name is checked automatically before other players can see it. It first goes through our own word filter and is then sent to TypeSafe AI (see section 7), whose model Jev assesses whether it is insulting, sexual, hateful or violent, is about drugs, contains contact details or poses as Brainelo staff. For each rejection we keep the date, the reasons and the rejected name. Since app version 0.1.96 there are no profile pictures: every player appears as a brain avatar dressed with items from the game. The pictures uploaded before were deleted; of pictures rejected before then we keep only the date, the reasons and a SHA-256 hash (never the picture itself). After four clear rejections, name changes are locked until our team lifts the lock (contact support), and the account is marked for our team to review. Legal basis: our legitimate interest in protecting all players, including minors, from harmful content (Art. 6(1)(f) GDPR).

Enforcing bans: for signed-in accounts we record which device identifiers and IP addresses the account uses (at most once every 5 minutes). If we ban an account for breaking our rules, its device identifiers and a SHA-256 hash of its email address (not the address itself) go on a ban list — in serious cases also the IP addresses of the last 30 days, for 7 or 30 days. A new account on a banned device or with a banned email address is banned automatically. The ban list is kept as long as the ban lasts, also after the banned account is deleted, so that a banned player cannot simply return with a new account. The devices, IP addresses and profile check records stored for your account are included in your data export (see section 6). Legal basis: our legitimate interest in a safe game and in enforcing our Terms of Use (Art. 6(1)(f) GDPR).

If you buy Brainelo Pro, Google Play or, on iPhone and iPad, the App Store processes the payment under Google’s or Apple’s own privacy policy — we never see your payment details. To unlock Pro on all your devices, RevenueCat receives your account identifier, the store receipt and your subscription status, plus basic technical data (platform, app and operating-system version, country). For the family plan, our server stores the owner’s subscription status and who belongs to the family, so that the members get Pro. The free trial runs on our own server and involves no payment data. Legal basis: performance of the contract, Art. 6(1)(b) GDPR.

With your consent, the game — in the browser and in the mobile app — uses Google Analytics for Firebase to understand how the product is used, for example onboarding steps, which games are played, and retention. Firebase then collects a pseudonymous app-instance identifier and technical device data (device model, operating system, app version, language, screen size, country). The app shows no ads.

Usage analytics is off by default on every platform and starts only once you agree. The app asks you during onboarding, and you can change your choice at any time in the app under Profile → Settings → Privacy & Data (switch “Usage analytics”). Once analytics is on, a second switch there, “Personalize my data”, is on by default: it lets the analytics data be linked to your account, and while it is off the data is not linked to your account. You can withdraw your consent at any time, with effect for the future. We keep a record of your choice and its date, on your device and with your account, as proof of consent. App versions before 0.1.88 could record Firebase’s automatic “first open” event before you were asked, and in the browser Google’s analytics script could load before you had made your choice; since 0.1.88, analytics starts only after your consent.

Legal basis: your consent, Art. 6(1)(a) GDPR, and — for storing and reading information on your device — § 25(1) TDDDG (German Telecommunications Digital Services Data Protection Act).

Onboarding statistics (first-party, in the browser and the mobile app): to see where our introduction loses or confuses new players, the game reports — to our own server in Germany only, never to Google or any other third party — in two parts. Step counts, for everyone: which steps of the first-run introduction are reached (screens, the terms, the first games, the end), how long each screen stays open and whether the introduction is finished or skipped. Each count is sent on its own, without any identifier, and counts cannot be linked to one another, to a device or to an account. We are comparing two versions of the introduction: which one you see is picked at random on its first screen and kept on your device until the introduction ends — so that you see the same version if you come back to it — and then deleted; apart from this, nothing is stored on or read from your device for the counts. A count contains only the step, which of the two versions of the introduction you were shown, the app version, platform and app language, whether analytics is switched on, and your country. Our own server looks the country up from your IP address in a local copy of the DB-IP Lite database; the IP address is not passed on to anyone and is not stored (IP geolocation by DB-IP (db-ip.com), licensed CC BY 4.0). Detailed statistics, only if you switch analytics on: from the introduction’s privacy screen on (or from the start, if analytics was already on), the game also reports taps on buttons and answer options (not the birth year you pick), scrolling, when the app goes to the background or is closed, how the introduction games and the Pro offer end, the operating system version and the screen size. These records carry a random identifier that is created on your device only for this purpose and deleted from your device when the introduction ends; they are linked to your account only if “Personalize my data” is on as well. Switching analytics off stops them at once and deletes the identifier from your device. Legal basis: for the step counts, our legitimate interest in an introduction that works (Art. 6(1)(f) GDPR); for the detailed statistics, your consent (Art. 6(1)(a) GDPR, § 25(1) TDDDG), which you can withdraw at any time with effect for the future. You can object to the step counts at any time: switch analytics on and then off again on the introduction’s privacy screen (all reporting stops right there; your device keeps a note of the objection), or write to the email address in section 1. All records are deleted after 180 days. App versions up to 0.1.82 created the identifier on the first screen, before you could switch analytics on; since 0.1.83 it is only created with your consent.

Satisfaction statistics (first-party, in the browser and the mobile app): to understand how satisfied players are with the game and to pick a good moment to ask for a store review, the app keeps a satisfaction score on your device. Important actions add or remove points: opening the app, finishing, winning or quitting a game, thumbs up or down on a game, sharing results and inviting friends, challenges and friends added, achievements, streaks and league results, starting or managing a purchase, sending a support request and switching notifications off. Each of these actions is sent to our own server in Germany only — never to Google or any other third party — together with the points it gave, the resulting score, the app version and the platform, linked to your account. No free text, names or email addresses are included. Legal basis: our legitimate interest in understanding satisfaction with our app and in asking for reviews only when it suits you (Art. 6(1)(f) GDPR). The statistics are on by default, except for players under 16 (section 10): for them they stay off and nothing is stored. You can object at any time with the “Satisfaction statistics” switch in the app under Profile → Settings → Privacy & Data: turning it off stops the reporting and deletes the statistics already stored with your account; you can also write to the email address in section 1. The statistics are deleted after 180 days and immediately when you delete your account.

To find and fix crashes, the mobile app (not the browser version) sends crash reports to Firebase Crashlytics (Google). A report contains the error and its stack trace, the device model, operating system and app version, and a pseudonymous installation identifier created by Crashlytics. It contains no username, email address or gameplay data and is not linked to your account. Legal basis: our legitimate interest in an app that works reliably (Art. 6(1)(f) GDPR); storing the installation identifier on your device is strictly necessary to provide the app you asked for in working order (§ 25(2) no. 2 TDDDG). You can object at any time by writing to the email address in section 1. Crashlytics deletes crash reports after 90 days.

Ad measurement (Android app only, optional): we advertise Brainelo on Google and Meta and want to know which of our Google Ads campaigns bring new players. After the introduction the app asks you once (“Allow” or “No thanks”); you can change your answer at any time with the “Ad measurement” switch under Profile → Settings → Privacy & Data. Only if you allow it, Google Analytics for Firebase may use your device’s advertising ID to tell Google Ads whether an install, a finished introduction, a free trial or a purchase came from one of our ads (Google Consent Mode v2: ad storage, ad user data and ad personalization are granted only then), and RevenueCat collects the advertising ID and device identifiers so that trials and purchases can be attributed to our Google Ads campaigns. These conversions are analytics events, so they are only sent while usage analytics is switched on as well — this includes measuring installs (“first open”). The app contains no Meta (Facebook) SDK and sends no data to Meta. Without your consent none of this happens; if you withdraw it, no further identifiers are collected, and identifiers already sent stay with RevenueCat until your account is deleted. The app shows no ads. Legal basis: your consent, Art. 6(1)(a) GDPR, and § 25(1) TDDDG.

• Google Analytics for Firebase privacy
• Firebase privacy and security (incl. Crashlytics)
• IP geolocation by DB-IP (CC BY 4.0)

If you allow notifications, a push token for your device is stored on our server and reminders such as your daily challenge are delivered through Firebase Cloud Messaging (Google). The token is stored only while notifications are allowed: if you switch notifications off in the app (Profile → Settings), it is removed from our server; if you only block them in your device settings, the token is no longer used. So that the daily streak reminder arrives at the time you picked, the app stores that time, whether the reminder is on and your device’s time zone with your account on our server. For each notification we record when it was sent, whether it reached your device and whether you opened it; we use this to send you at most two notifications a day (replies to your support requests aside), to hold them back between 10 pm and 8 am your time, and to see which ones are useful. These records are deleted with your account. Legal basis: your consent, Art. 6(1)(a) GDPR.

If you turn on the weekly recap, we email a summary of your week (games played, ratings, streak) to your account’s email address through our email provider Resend. You can turn it off at any time in the app under Profile → Settings → Notification Settings, or with the link in every email. Legal basis: your consent, Art. 6(1)(a) GDPR.

Wellbeing check-ins (in the browser and the mobile app, optional): after a training day that cost you Elo — and at most once a week after a good one — the app can ask three one-tap questions: how you slept last night, how stressed you are and how much energy you have. Your answers are information about your health (Art. 9 GDPR), so we only ask after you have explicitly agreed, in the check-in itself or with the “Wellbeing check-ins” switch under Profile → Settings → Privacy & Data. We store the answers with the date and that day’s Elo change on our own server in Germany, linked to your account, to give you a tip and, once there are enough check-ins, to show you your own pattern in Statistics (for example how your training went after good and after rough nights). They are never shared with Google or any other third party, never used for analytics, advertising or any other purpose, and not visible to other players. This is not medical advice, and the app makes no diagnosis. The check-ins are not offered if your birth year says you are under 16. Legal basis: your explicit consent, Art. 9(2)(a) and Art. 6(1)(a) GDPR. You can withdraw it at any time with the same switch; turning it off deletes every answer stored with your account.

If you join the iPhone waitlist (on our website or in the web app), we store your email address, language, signup date, where you signed up (website or app), your platform and — if you are signed in — your account identifier, and we send you a confirmation email through Resend. Only once you confirm are you on the list; we then email you once, on the day Brainelo launches on the App Store, with an unsubscribe link. If you don’t confirm, you get no further emails. You can unsubscribe at any time with the link in the emails. Legal basis: your consent, Art. 6(1)(a) GDPR.

If you request a copy of your data (Profile → Account → Export My Data), we store it in a private Google Cloud Storage bucket and email you a download link through Resend. The link works for 7 days; the file is then deleted. Legal basis: your rights of access and to data portability, Art. 6(1)(c) GDPR in conjunction with Art. 15 and 20 GDPR.

If you own a family plan and invite someone by email (Profile → Family → Invite by email), we send that person one email with your name and your invite link through Resend, in your app language. We use the address only for that one email and do not store it. When someone joins your family, we tell you with a notification and an email to your account’s email address. Legal basis: providing the family plan, Art. 6(1)(b) GDPR; for the invited person, our and your legitimate interest in delivering the invitation you asked for, Art. 6(1)(f) GDPR.

The Android home-screen widget shows your streak using data the app has already stored on your device; it sends nothing to us.

Personal data is shared only with the following providers, and only as far as necessary. We never sell personal data and we show no advertising.

• Hetzner Online GmbH (Germany) — runs the servers for our game database, our API and the browser game (api.brainelo.de, play.brainelo.de) in a data centre in Nuremberg, Germany, under a data processing agreement (Art. 28 GDPR).
• Google (Firebase Authentication, Cloud Messaging, Remote Config, Analytics for Firebase, Crashlytics and Firebase Hosting for brainelo.de; Google Cloud Storage for files you attach to support requests and for the download of a data export you request). For transfers to the USA, Google is bound by the EU Standard Contractual Clauses.
• Google Ads (Google) — only with your ad-measurement consent: receives conversion events (install, finished introduction, trial, purchase) through Google Analytics for Firebase (see section 5). For transfers to the USA, Google is bound by the EU Standard Contractual Clauses.
• RevenueCat (RevenueCat, Inc., USA) — manages Brainelo Pro subscriptions (see section 4) and, only with your ad-measurement consent, receives device identifiers for ad attribution (see section 5). For transfers to the USA, RevenueCat is bound by the EU Standard Contractual Clauses.
• Resend (USA) — sends our emails: the weekly recap, data-export links, the family plan emails (invitations and “joined your family” notices) and the iPhone waitlist emails (confirmation and launch email). For transfers to the USA, Resend is bound by the EU Standard Contractual Clauses.
• TypeSafe AI (TypeSafe AI, Inc., USA) — automatically checks new display names before they are shown (see section 4), under a data processing agreement. It does not use them to train its models. For transfers to the USA, TypeSafe is bound by the EU Standard Contractual Clauses.
• Our own monitoring (server logs and metrics) runs on a machine we operate ourselves in Germany, which reaches the servers only through an encrypted VPN. It also keeps an encrypted copy of our backups.

• Account and gameplay data: until you delete your account. Deletion is immediate and permanent; the Account Deletion page lists what is deleted.
• Deletion record: after a deletion we keep only the account identifier, the time of each deletion step and the names (not the contents) of deleted files, for 35 days after the deletion is complete. It lets us finish deleting at our service providers, apply the deletion again if a backup ever has to be restored, and stop an old login from re-creating the account.
• Backups: stored encrypted and deleted after at most 30 days.
• Guest profiles: a guest sign-out ticket is valid for 30 days. When a guest profile is merged into an account, the guest profile and its anonymous sign-in are deleted within about a day.
• Data exports: the download link works for 7 days; the file is then deleted.
• Server and monitoring logs (IP address, user agent, requested address, time): at most 30 days. Server metrics: 15 days.
• Profile check records (rejected names, and SHA-256 hashes of pictures rejected before app version 0.1.96, see section 4): until you delete your account.
• Devices and IP addresses an account was seen on: IP addresses for 30 days; device identifiers until you delete your account.
• Ban list (device identifiers, email hash and, in serious cases, IP addresses for up to 30 days): as long as the ban lasts, also after the banned account is deleted.
• Website logs of brainelo.de: kept by Google Firebase Hosting for a limited period.
• Usage analytics: Google Analytics deletes user- and event-level data after the retention period set for our property, at most 14 months.
• Crash reports: deleted by Firebase Crashlytics after 90 days.
• Onboarding statistics: deleted from our server after 180 days; the random identifier of the detailed statistics is removed from your device when the introduction ends or analytics is switched off.
• Satisfaction statistics: deleted from our server after 180 days, when you turn off the “Satisfaction statistics” switch, or when you delete your account.
• Wellbeing check-ins: until you turn off the “Wellbeing check-ins” switch, which deletes them at once, or delete your account.
• iPhone waitlist: until the launch email has been sent, after which we delete the list — or earlier, when you unsubscribe or delete your account. After an unsubscribe we keep only your email address, marked as unsubscribed, so that you get no further emails.
• Google Play purchases: Google keeps its own purchase records under Google’s terms.
• Aggregated, anonymous statistics: kept indefinitely — they no longer constitute personal data.

Under the GDPR you have the right to:

• Access to your data (Art. 15), rectification (Art. 16), erasure (Art. 17), restriction of processing (Art. 18) and data portability (Art. 20);
• Object to processing based on legitimate interests (Art. 21);
• Withdraw consent at any time, where processing is based on consent (Art. 7(3)).

To exercise any of these rights, email klausgreinerdev@gmail.com — we respond within one month. In the app you can also download a copy of your data (Profile → Account → Export My Data, for registered accounts) and delete your account (Profile → Account → Delete Account). You also have the right to lodge a complaint with a data protection supervisory authority, in particular in the EU member state of your residence or of our establishment.

The service is not directed at children. If the birth year you enter says you are under 16 (this includes the calendar year you turn 16), usage analytics, ad measurement, the satisfaction statistics (section 5) and the wellbeing check-ins (section 6) stay switched off and the app does not ask for them. The other features that rely on your consent (notifications, the weekly recap and the iPhone waitlist) you may use only with the consent of a parent or guardian (Art. 8 GDPR). We do not verify ages: the birth year you can enter during onboarding is used only for your age group, the comparison with players of your age, keeping those features off and our team’s internal statistics on how old our players are, which are never shown to other players or shared with anyone (our legitimate interest in knowing which ages the game reaches, Art. 6(1)(f) GDPR). If you believe a child under 16 has given us personal data without a parent’s consent, contact us and we will delete it.

All connections to the service are encrypted in transit (HTTPS/TLS), our backups are encrypted at rest, our monitoring reaches the servers only through an encrypted VPN, and access to production data is restricted. No method of transmission or electronic storage is 100% secure — but we protect your data with measures appropriate to its sensitivity.

We may update this policy as the service evolves. Any change is published on this page with a new “last updated” date. Significant changes will be announced in the app as well.