Privacy Policy — MindBuy

Last updated: 10 October 2026 · applies from app version 2.0

1. Controller

The controller responsible for data processing within the meaning of the GDPR is:

Contact for data protection enquiries: support@elephanttrails.de

2. Scope

This Policy applies to the MindBuy app in its current version and to the associated pages at elephanttrails.de/mindbuy.

MindBuy is distributed via the Google Play Store. A version for iOS (Apple App Store) is in preparation; the differences that apply there are already taken into account in this Policy.

3. What changed with version 2.0

Earlier versions of this Policy stated that MindBuy works without an account, without a server and without the cloud. That has no longer been the case since version 2.0. The main changes:

• A user account is required to use the app.
• In addition to being stored locally, your entries are kept as a backup copy in the cloud.
• There are push messages from a server (announcements), in addition to the reminders, which remain purely local.
• The premium features are provided as a subscription instead of a one-off purchase.

What has not changed: there are still no analytics or crash-reporting services, and your entries are neither sold nor evaluated for advertising. Advertising tracking only happens with your permission (see section 10).

4. User account

An account is required to use MindBuy. The app cannot be used without one. The reason is the cloud backup: it needs a fixed assignment so that your data can be found again after you switch devices.

Sign-in options: sign in with Google or with Apple. There is no sign-in with an email address and password.

Data processed: email address, display name (if provided by the sign-in service), a user ID assigned by Firebase (UID), the times the account was created and last signed in, and technical connection data such as the IP address.

If you use “Sign in with Apple”, you can choose at Apple to hide your email address. In that case we only receive the relay address generated by Apple, not your real one.

Technical service: Firebase Authentication (Google Ireland Limited).

Legal basis: Article 6(1)(b) GDPR — performance of the contract for use.

Storage period: until the account is deleted (see section 19).

5. Data stored on your device

This data is kept in an SQLite database and in the app settings in the protected app directory on your device:

Content

• Name, description and notes of your entries
• Price and currency
• Optional product link and shop name
• Category and status (waiting, released, bought, discarded, planned)
• Points in time: creation, end of the waiting period, purchase or discard, planned date
• Savings goals with target amount and progress
• Monthly budgets
• Statistics, achievements and decision streak

Settings

• Language, currency and colour theme
• Notifications on or off
• Consent to personalised advertising
• Subscription status
• Progress in welcome and tip texts
• Time of the last backup and of the last version check

Legal basis: Article 6(1)(b) GDPR.

Storage period: until you delete the data or uninstall the app. When the app is uninstalled, the operating system removes this directory completely — the cloud backup is not affected.

6. Cloud backup

MindBuy stores a copy of your database in your account. This happens when you back up manually in settings, on first sign-in on a device, and automatically at most once every 24 hours.

The backup is free for all users and is not tied to the subscription.

Data processed: the full content from section 5 — entries, savings goals, budgets, statistics and achievements.

Storage: as a file under users/<UID>/backup/mindbuy.db in Firebase Storage. Access is restricted by security rules to your own account; other users have no technical access.

Storage location: a Google data centre in Frankfurt am Main, Germany (region europe-west3).

Transmission: encrypted via TLS.

Legal basis: Article 6(1)(b) GDPR.

Storage period: until the account is deleted, or until you create a new backup in the app that replaces the previous one. To protect against accidental deletion, the storage keeps deleted files technically recoverable for another 7 days; after that they are permanently removed.

7. Marker of the former trial period

Until October 2026, every new account got the additional features for seven days. For this, the start time was stored once in your account — as the file users/<UID>/trial/start.json. The trial period no longer exists; no new files are created. Existing files are deleted together with the account.

Data processed: a timestamp only.

Legal basis: Article 6(1)(f) GDPR — legitimate interest in granting a free trial period only once.

Storage period: until the account is deleted.

7a. Inviting friends (Android only)

You can invite others to MindBuy with an invitation code. If a new account redeems your code, you both get the additional features for 14 days. Taking part is voluntary; without an invitation, the following data is not created.

Data processed:

• Your invitation code — it is calculated from your user ID. So that it can be redeemed, we store which user ID it belongs to (referral/codes/<Code>.json). Signed-in users who know your code can look up this assignment; a list of all codes cannot be retrieved.
• Redemption — your account records that and when you redeemed a code and which user ID it came from (users/<UID>/referral/redeemed.json).
• Reward — a file named after your user ID, together with the time, is stored in the account of the person who invited you (users/<inviter's UID>/referrals/<your UID>.json). In the app, the inviting person only sees the number of their invitations, no names and no email addresses.

Names, email addresses and the contents of your wish list are not passed on in the process. You send the invitation text yourself using an app of your choice; MindBuy does not learn to whom.

Legal basis: Article 6(1)(b) GDPR — running the invitation programme you take part in.

Storage period: until the account is deleted. If the invited person deletes their account, the reward file in the inviting person's account is removed as well.

8. Reminders and announcements

Reminders (local). When the waiting period of an entry ends, the app reminds you. These notifications are scheduled and triggered exclusively on your device. No data is transferred. So that the reminders survive a restart, they are rescheduled after the device boots.

Announcements (push). In addition, MindBuy can occasionally send notices about the app — for example about major new features. For this, the device is registered with Firebase Cloud Messaging for the “all” channel.

Data processed: a device identifier assigned by Google (FCM token). The channel is topic-based; messages are not linked to you personally.

Legal basis: Article 6(1)(a) GDPR — consent given by granting the notification permission. You can withdraw it at any time in the app or system settings.

9. Version check

MindBuy checks at most once every 24 hours whether a newer version is available. To do so, the app downloads a small configuration file (config/app_version.json) from Firebase Storage. Only the technically unavoidable connection data, in particular the IP address, is transmitted. No user ID is sent.

Legal basis: Article 6(1)(f) GDPR — legitimate interest in a current, working version.

10. Advertising

In the free version, MindBuy shows advertising via Google AdMob:

• a banner at the bottom of the home screen,
• a full-screen ad when you return to the app from the background, at most once per hour,
• a full-screen ad after you save a new entry, at most once every three minutes.

No full-screen ad appears when the app starts or during setup.

During an active subscription and while gifted additional features from an invitation are running, no advertising is shown.

Consent (EU, EEA, United Kingdom, Switzerland): Before any ad is loaded, MindBuy asks for your consent via Google's consent platform (User Messaging Platform, a CMP certified by Google). Until you have made a choice, the advertising library is not even started. If you decline, Google delivers only limited ads, without storing data on your device or reading data from it. You can change or withdraw your choice at any time under Settings → Privacy options for advertising.

On iPhone and iPad, the first time the home screen opens MindBuy uses Apple's "App Tracking Transparency" prompt to ask whether the app may recognise you for advertising across other companies' apps and websites. Google's consent dialog follows only after that.

• Allowed: AdMob may use your device's advertising identifier (IDFA), and ads may be personalised — provided you also agree in Google's dialog.
• Not allowed: only non-personalised advertising is delivered; the advertising identifier stays inaccessible to MindBuy.

You can change this at any time on your device under Settings → Privacy & Security → Tracking.

On Android, personalisation is off by default. On first launch you are asked whether personalised advertising should be allowed; the setting can be changed at any time under Settings → Personalised advertising.

• Consented: AdMob may use your device's advertising ID and related usage data.
• Not consented: only non-personalised advertising is delivered.

Data processed by AdMob: advertising ID, device model and operating system version, approximate location based on IP address (no GPS), app version, and — where personalisation is enabled — interactions with ads.

You can reset or delete the advertising ID at any time in your device's system settings.

Legal basis: for personalised advertising, Article 6(1)(a) GDPR (consent); otherwise Article 6(1)(f) GDPR (legitimate interest in financing the free version).

11. Subscription and payments

The additional features (“MindBuy Plus”) are offered as a subscription. Payment is handled exclusively via the Google Play Store, and on iOS via the Apple App Store.

• We receive no payment data — neither card nor account numbers.
• We only learn whether a subscription is active, in order to unlock the features. This check takes place on the device.

Legal basis: Article 6(1)(b) GDPR.

12. Importing a product link from other apps

If you share a product link with MindBuy from another app, the app retrieves this page once, directly from your device, to read the name and price. There is no detour via a server of ours.

The website accessed sees your IP address and technical details of your device — as with any page request. We have no influence on how it processes data.

Legal basis: Article 6(1)(b) GDPR.

13. Export and import as a file

In addition to the cloud backup, you can export your data as a file and import it again.

• The file contains all content from section 5.
• It is not encrypted.
• Where it goes — a local folder, email, someone else's cloud storage — is up to you. From that moment on, it is outside our sphere of influence.

14. Permissions

Each of these permissions can be withdrawn in the system settings.

15. No analytics services

MindBuy uses no analytics, statistics or crash-reporting services. In particular, Firebase Analytics and Firebase Crashlytics are not included, even though other Firebase components are used.

What you record, buy or discard is not evaluated. There is no profiling and no automated decision-making.

Advertising is separate: with your permission, AdMob may use the advertising identifier for personalised ads (see section 10). The contents of your wish list are never shared.

Should this change in a future version, this Policy will be updated beforehand and you will be notified in the app.

16. Recipients and processors

A data processing agreement under Article 28 GDPR is in place with Google for the Firebase services.

Your data is not sold, and it is not passed on to third parties for their own advertising purposes.

16.1 Transfers to third countries

The Google services mentioned are provided by Google Ireland Limited but may technically be processed in the USA. Google LLC is certified under the EU-US Data Privacy Framework; the transfer is therefore based on the European Commission's adequacy decision of 10 July 2023 (Article 45(3) GDPR). In addition, Google has implemented the European Commission's Standard Contractual Clauses (Article 46(2)(c) GDPR).

The same applies to Apple.

You should know: under certain conditions, US authorities can access data processed by US companies. The Data Privacy Framework provides a complaint procedure for this via the Data Protection Review Court.

Further information: policies.google.com/privacy · firebase.google.com/support/privacy · apple.com/legal/privacy

17. Storage periods at a glance

18. Data security

• Local data is kept in an app-specific directory that the operating system shields from access by other apps.
• The local database is not additionally encrypted. If an unencrypted device is lost, the data is technically readable — the operating system's device encryption should be active.
• The cloud backup is kept in an area separated by account; the access rules permit access only from your own account.
• All of the app's network connections run over TLS.

19. Your rights

You have the right of access (Article 15), rectification (Article 16), erasure (Article 17), restriction of processing (Article 18), data portability (Article 20) and objection (Article 21 GDPR). You can withdraw any consent you have given at any time with effect for the future (Article 7(3) GDPR).

You can take care of much of this yourself, directly:

• Access and portability: you can see all content in the app; under Settings → Data → Export you get it as a file.
• Erasure: Settings → Delete account. This removes the account, the cloud backup, the trial period marker, the invitation data and all data on the device — wishes, history, savings goals, budgets and achievements. This cannot be undone. The files in the cloud then remain technically recoverable for 7 days and are then permanently deleted. On iOS, the Apple sign-in token is also revoked, so MindBuy disappears from your Apple ID settings as well.
• Objecting to personalised advertising: on Android via the switch in settings, on iPhone and iPad under Settings → Privacy & Security → Tracking. In addition, at any time via Settings → Ad privacy options in the app.

For anything else, an email to support@elephanttrails.de is enough.

You can also lodge a complaint with a supervisory authority, generally the data protection authority of your federal state.

20. Children

MindBuy is not aimed at children and is intended for use from the age at which a person can consent to data processing on their own in the respective country (16 in Germany, Article 8 GDPR).

21. Changes to this Policy

This Policy is updated when features or legal conditions change. In the event of significant changes, you will be notified the next time you start the app. The version at elephanttrails.de/mindbuy/en/privacy applies in each case.

Last updated: 10 October 2026