গোপনীয়তা নীতি

Last updated: 29 October 2026

1. Controller

BTechnology GmbH, Immermannstr. 19, 40210 Düsseldorf, Germany. Email: contact@matemind.app

2. The app at a glance

MateMind works without an account. Your progress, rating, streak, courses and games are stored on your device and are not automatically sent to us. The app uses PostHog for pseudonymous usage statistics and error reports (section 3). Purchases run entirely through the Apple App Store (section 5).
When you delete the app, all locally stored data is deleted with it.

3. Usage statistics and error reports with PostHog

To understand which features are used and where the app has problems, the app sends usage events and error reports to PostHog. The provider is PostHog Inc., 2261 Market Street #4008, San Francisco, CA 94114, USA. The data is stored in the PostHog EU cloud in Frankfurt am Main, Germany. Where PostHog Inc. or its subprocessors access it from the USA, the transfer is covered by PostHog's certification under the EU-US Data Privacy Framework (Art. 45 GDPR) and additionally by EU Standard Contractual Clauses (Art. 46(2)(c) GDPR).
What is sent: which screens and features you use (for example puzzle solved, course started, game against a bot finished), onboarding steps, your chosen daily goal and app language, rough results such as rating changes, offers shown and purchase-dialog outcomes, and details the PostHog SDK sends automatically: app version and build, device model and type, operating system and version, language and region, time zone, screen size, network type and SDK version. If the app runs into an error, a technical error report with the type of error and the affected code location is sent. PostHog derives an approximate location (country and city) from your IP address. The events are linked to a randomly generated, pseudonymous identifier. They contain no names and no email addresses. There is no screen recording and no tracking across apps or websites of other companies.
The legal basis is our legitimate interest in a working and improving app (Art. 6(1)(f) GDPR). You can object at any time by turning off "Share usage statistics" in the app settings; after that the app sends no more usage events or error reports. We delete event data no later than 12 months after it was collected.

If you send feedback from the app settings, we send your message together with the app version, app language, your rating and the random app identifier to PostHog, even if usage statistics are turned off, because sending it is then your own choice (Art. 6(1)(a) GDPR). Please don't include personal data such as your name or email address unless you would like a reply.

4. Remote settings

The app regularly loads settings from PostHog (feature flags), for example to show a note when a new app version is available. The same identifier and technical data as in section 3 are used.

5. Purchases

Hint packs, ad removal and Premium are sold through the Apple App Store. Apple processes the payment. We receive no payment details such as credit card numbers, only the confirmation from Apple that a purchase is valid.

We use RevenueCat (RevenueCat, Inc., USA) to manage purchases and subscriptions. RevenueCat receives Apple's purchase receipts and a random app identifier, no names or email addresses. We use it to check whether a subscription is active and to restore purchases on new devices (Art. 6(1)(b) GDPR). Transfers to the USA are based on the European Commission's standard contractual clauses.

6. Advertising

MateMind is free and is financed by ads and optional purchases. Ads are delivered by Google AdMob (Google Ireland Limited, Gordon House, Barrow Street, Dublin 4, Ireland), which can also broker ads from other ad networks. The app shows no ads during your first puzzles. Before the first ad, users in the EU, EEA, UK and Switzerland are asked through Google's consent form whether they agree to personalized ads, and iOS asks whether apps may track you across other companies' apps.

If you agree, Google and the networks it works with receive your device's advertising ID, approximate location derived from your IP address, device data and information about which ads you saw (Art. 6(1)(a) GDPR). If you don't agree, the app only shows non-personalized ads without the advertising ID. You can change your consent at any time in the app under Settings > Ad privacy, and withdraw it in iOS Settings under Privacy > Tracking. With Premium or the "No Ads" purchase you see no ads at all. How Google uses data is explained at https://policies.google.com/technologies/partner-sites.

7. Apple Search Ads

If you installed MateMind after tapping an ad in the App Store, the app asks Apple once, using the AdServices framework, which campaign led to the installation. Apple returns campaign information without personal data. We use it to measure our App Store advertising (Art. 6(1)(f) GDPR). No tracking across apps takes place.

8. Game Center, invites and notifications

If you use Game Center, your scores and achievements are processed by Apple under Apple's privacy policy. Daily reminders are created on your device as local notifications; no data is sent to us for them. You can turn reminders off in the app or in the iOS settings at any time.

For inviting friends, MateMind uses Apple's public iCloud database. It stores a hash of your iCloud user identifier (not your Apple ID, no name, no email address), the fact that MateMind was installed with this identifier before, which invite code was redeemed and which invites have already been credited. This ensures that each invite is rewarded only once (Art. 6(1)(b) GDPR). When a friend redeems your code, Apple sends you a notification. Without an iCloud sign-in, no invite data is stored.

MateMind backs up your progress (rating, streak, hint bulbs, solved puzzles and settings) to your private iCloud database at Apple, so it comes back on a new device or after reinstalling. Only you and your devices can access this data, we cannot (Art. 6(1)(b) GDPR). Without an iCloud sign-in, progress stays on the device only.

9. This website

This website is hosted by Netlify, Inc., 101 2nd Street, San Francisco, CA 94105, USA. When you visit, Netlify processes technically necessary data such as IP address, time, page requested and browser type to deliver the site and protect it from abuse. The legal basis is our legitimate interest in secure operation (Art. 6(1)(f) GDPR). Netlify is certified under the EU-US Data Privacy Framework. The website loads no external fonts and shows no ads.

Only if you agree in the cookie notice shown when you visit the website do we use Google Analytics to understand how the website is used, for example which pages are viewed and which links visitors come from. The provider is Google Ireland Limited, Gordon House, Barrow Street, Dublin 4, Ireland. For this, Google sets cookies (_ga and _ga_<ID>, lifetime up to 2 years) and processes your IP address, a random identifier, the pages you view, the previous page, date and time, device type, browser, operating system, screen size, language and an approximate location (country, region, city) that Google derives from the IP address. Google Analytics does not store the IP address. Google deletes data about individual visitors after 14 months at the latest. Google may also transfer data to Google LLC in the USA; Google LLC is certified under the EU-US Data Privacy Framework (Art. 45 GDPR). More at https://policies.google.com/privacy.
The legal basis is your consent (Art. 6(1)(a) GDPR, Section 25(1) TDDDG). If you decline, Google Analytics is not loaded and no cookies are set. We store your choice only in your browser (local storage) so the notice doesn't appear on every page. You can withdraw your consent at any time via "Cookie settings" in the footer of every page; the website then deletes the analytics cookies from your browser.

10. Contact

If you write to us, we use your message and email address only to handle your request. We delete them once the request is resolved, unless legal retention periods apply.

11. Your rights

You have the right to access, rectification, erasure, restriction of processing, data portability and objection. Write to contact@matemind.app.
You can also lodge a complaint with a data protection authority, for example the State Commissioner for Data Protection and Freedom of Information of North Rhine-Westphalia.

12. Changes

If we add new features or services to the app, we update this policy beforehand. The version published here applies.