Prover Deutsch

Privacy policy

How your data is protected

This English version is a convenience translation. Only the German version is legally binding. Where the two differ, the German version prevails.

1. Controller

The controller responsible for data processing within the meaning of the General Data Protection Regulation (GDPR) is:

Alexander Knor
Westring 1
33378 Rheda-Wiedenbrück
Germany

Email: prover.app.dev@gmail.com

If you have questions about data protection or want to exercise your rights, you can contact this address at any time.

2. Overview

Prover is a training app. For it to work, personal data is processed, in particular to sync your data between devices, for the AI features and to manage a subscription.

There is no advertising, no tracking for advertising purposes and no sale of your data. Only what is necessary to run the app, to provide the features you use and to keep the app stable is processed.

The following sections describe in detail which data is processed for which purpose, to whom it is disclosed and which rights you have.

3. Account data

For registration and sign-in, we process the following through Firebase Authentication (Google):

• Email address
• Password (stored encrypted by Firebase; we have no access to the password in plain text)
• Time of registration and of the last sign-in

We store your username with your profile in Cloud Firestore (Google).

You can also use Prover as a guest without registering. Firebase Authentication then creates an anonymous account: a random user ID without an email address and without a password. Your data is assigned to this user ID and stored as it would be for a registered account. If you create an account later, your data is kept.

The emails about your account, that is, to confirm your email address, to reset your password and to confirm a new email address, are sent by our server through the email service Resend (section 13). This transmits your email address and the content of the email with the confirmation link. If our server cannot send an email, Firebase Authentication (Google) sends it instead. The message to your previous address after a change of your email address is always sent by Firebase Authentication.

So that nobody can use Prover to trigger large numbers of emails to other people's addresses, our server stores, per kind of account email, a hash of the recipient address (not the address itself) with the times of sending for 24 hours. The legal basis for this is Art. 6(1)(f) GDPR (legitimate interest in protection against abuse).

Purpose: creating and managing your account, signing in, protection against unauthorized access.
Legal basis: Art. 6(1)(b) GDPR (performance of a contract).

4. Training and usage data

When you use the app, we store the content you create in the cloud database (Cloud Firestore, Google):

• Training plans you create and edit
• Completed workouts (exercises, sets, weights, reps, RIR, notes)
• Training progress, statistics, achievements and history
• Custom exercises and progression profiles. A progression profile you publish is visible to other users with your username until you make it private again.
• Weigh-ins (if you use weight tracking)
• Form checks, if you use them: their date, the estimated body fat range, the assessment of 14 muscle groups, the written reading, the comparison with the previous check and the time of your consent. We store the photos in Firebase Storage (see section 5).
• Nutrition data, if you use the nutrition features: your food diary (logged foods and meals with calories and nutrients), saved meals and recipes, calorie and macro targets including the details you provide for them (height, age, sex) and the energy expenditure calculated or measured from them, body fat entries and recently used foods
• Supplements and the doses you check off, if you use the supplement feature
• Profile details (e.g. bio and sex)
• Onboarding status and app settings, where they are synced with your account
• Support requests you send through the support form (subject, message, category, your email address)

Purpose: providing the app's features, storing and syncing your data between devices, handling support requests.
Legal basis: Art. 6(1)(b) GDPR (performance of a contract).

We store form checks and their photos only with your explicit consent, which you give before your first check (Art. 9(2)(a) GDPR), because they describe your body. You can withdraw it at any time in your profile under Form check consent. The app then deletes all checks and all form check photos in your account and on your device.

If you report a published progression profile, we store your user ID, the reported profile, the reason you chose, your note if you write one, and the time of the report. Only we read the report. The author of the profile does not learn who reported it. We delete the report as soon as we have handled it, at the latest when your account is deleted.

If we remove one of your profiles from the public list, it stays in your account as a private profile. We record the time on it. It can no longer be published after that. If we bar you from publishing, we record this on your account. The bar applies until we lift it or you delete your account. Reports and a bar are not included in the app's data export. We will tell you about them on request at prover.app.dev@gmail.com.

Purpose: moderating published content, protecting users from abusive content.
Legal basis: Art. 6(1)(f) GDPR (legitimate interest in published content free of abuse).

5. Photos and images

For the form check, you take photos with the camera or select them from your photo library. For the AI body fat estimate, you select photos from your photo library. To log a meal from a photo, you can take a photo or select one. For barcode scanning, the app uses the camera. The app accesses the camera or the photo library only when you explicitly act, and you can revoke this access in your device settings.

• The photos are sent to Google to produce the respective AI evaluation (see section 6). Prover does not store the photos of the AI body fat estimate or of a meal from a photo on its servers.
• We store the photos of your form checks without metadata such as the location in Firebase Storage in your account, so you can compare your checks and your history is there on each of your devices. Only your account can retrieve them. They are deleted when you delete the check, withdraw your consent or delete your account. The app's data export does not include them. We will send you a copy on request at prover.app.dev@gmail.com.
• On your devices, the app keeps a copy of the photos in the app's protected storage. It is excluded from device backups. The app removes it once the check is deleted, at the latest when the app is uninstalled.
• The camera image of the barcode scan is analyzed on your device. Only the recognized barcode is transmitted (see section 13).
• Earlier versions of the app also stored the photos of the AI body analysis in Firebase Storage. These copies are being deleted.

You decide yourself whether to provide images and which ones. Do not upload photos in which third parties can be recognized without their consent.
Legal basis: Art. 6(1)(a) GDPR (consent by actively using the feature) or Art. 6(1)(b) GDPR, for the form check Art. 9(2)(a) GDPR (explicit consent).

6. AI features

The app includes AI-powered features: the AI coach, the AI body analysis (form check), the AI body fat estimate and logging a meal from a photo. They are provided through Firebase AI Logic with Gemini models from Google (Vertex AI).

When you use an AI feature, the input it needs is sent to Google and processed there to generate a response:

• AI coach: your chat messages and the data of the area you open it from, e.g. your current or completed workout, your training history, your statistics or your weight history.
• Form check: the 1 to 3 photos of your body that you take or select for it and, where they exist, the photos of the same views from your previous check. The AI checks the photos, estimates your body fat and muscle development from them and compares them with the previous check. Each check sends up to five requests to Google.
• AI body fat estimate: the 1 to 3 photos of your body that you select for it. From them, the AI estimates your body fat.
• Logging a meal from a photo: the photo and your answers to follow-up questions about the meal.

Every AI request also contains the sign-in token of your account and an App Check attestation (see section 17). This ties the request to your account and to a genuine installation of the app, which protects the AI features from abuse. For the Prover Premium quotas, we count per account how many AI requests you have made in the current month or during the trial, without storing their content.

The AI results are automatically generated estimates, not medical, nutritional or exercise science advice, and they do not replace guidance from a qualified professional.

AI features are optional. They are only triggered when you actively use them.
Legal basis: Art. 6(1)(a) GDPR (consent by using the feature) or Art. 6(1)(b) GDPR, for the form check Art. 9(2)(a) GDPR (explicit consent).

7. Crash and diagnostic data

To detect and fix errors, we use Firebase Crashlytics (Google). When the app crashes or hits a serious error, technical data is transmitted automatically, e.g.:

• Error and crash reports (stack traces)
• Device model, operating system and its version
• App version, time of the error
• A pseudonymous installation identifier
• The app's log lines about warnings and errors. They may contain your pseudonymous user ID and names of training plans, training days, exercises or progression profiles.

This data is used solely to keep the app stable and to improve it.
Legal basis: Art. 6(1)(f) GDPR (legitimate interest in a working, error-free app).

8. Location data

When you tap the search for gyms nearby, the app asks for location permission if you have not granted it yet. It then determines your approximate location once to show gyms in the area. For the search, the app sends this location to the Overpass service for OpenStreetMap data (see section 13).

Your location is not stored permanently, not kept on our servers and not used for any other purpose. You can revoke the permission at any time in your device settings.
Legal basis: Art. 6(1)(a) GDPR (consent by using the feature).

9. Health data (Apple Health / Health Connect)

If you use the adaptive calorie calculation or "Live steps", you can connect your daily step count from Apple Health (iOS) or Health Connect (Android). The connection is only established if you explicitly allow it in the permission dialog of the operating system.

• Only your step count per day is read: for the adaptive calculation within its measurement period, and for "Live steps" that of the current day and the days before it, to adjust your daily target.
• The analysis takes place entirely on your device. Your step data is not transferred to our servers, not stored in the cloud and not shared with third parties.
• The app does not write any data to Apple Health or Health Connect.
• Health data is not used for advertising or similar purposes and is not sold.

You can revoke access at any time (iOS: in the Health app under "Data Access & Devices"; Android: in the Health Connect settings). The step display then disappears and your daily target follows your estimated everyday activity again; all other features remain unaffected.
Legal basis: Art. 9(2)(a) in conjunction with Art. 6(1)(a) GDPR (explicit consent by granting the system permission).

10. Subscription and purchase data

If you try or subscribe to Prover Premium, we process data about your subscription.

We do not see any payment data. The purchase is handled entirely by Apple or Google. Card numbers, bank details and billing addresses are never transmitted to us.

We process:

• The status of the subscription (active, canceled, expired), the chosen product, the billing period and the expiry date
• Your user ID, so that the purchase can be assigned to your account
• The start and end of a trial

We do not collect a device identifier. Whether you are eligible for a free trial is decided solely by the respective app store based on your store account; we only learn the result.

We use RevenueCat to manage and verify subscriptions. Details are in sections 13 and 14.

The legal basis is Art. 6(1)(b) GDPR for the performance of the contract for Prover Premium.

11. Notifications

The app can show local notifications (e.g. when the rest timer runs out). They are generated on your device; no personal data is transmitted to us or third parties for this. You can manage the notification permission in your device settings.
Legal basis: Art. 6(1)(b) GDPR.

12. Data stored locally on your device

Some data is stored only locally on your device and is not transferred to us, including:

• app settings and preferences (in the device's local storage)
• the authors of published progression profiles you have hidden. They are not told about it.
• the list of profiles you have reported (section 4 describes the report itself)
• security-related tokens (encrypted in the device's secure storage)
• cached content, so that the app works offline and faster

This data is removed from the device when you uninstall the app. If you delete your account, the app also removes that account's data from the device, such as recently logged foods, an unfinished workout and cached training plans and progress.

13. Recipients and processors

We use services from Google to provide the app's services.

As part of the Firebase platform of Google Ireland Limited or Google LLC:

• Firebase Authentication (sign-in)
• Cloud Firestore (data storage)
• Cloud Functions for Firebase (syncing subscriptions, deletion on the server, sending account emails)
• Firebase Storage (exercise videos, photos of your form checks)
• Firebase Crashlytics (error and crash reports)
• Firebase AI Logic with Vertex AI and Gemini (AI features)
• Firebase App Check (protection against abuse)

We have concluded a data processing agreement with Google in accordance with Art. 28 GDPR. Google is certified under the EU-U.S. Data Privacy Framework.

To manage and verify subscriptions, we use RevenueCat, Inc., 1032 E Brandon Blvd #3003, Brandon, FL 33511, USA. RevenueCat receives your user ID, the purchase receipts of the respective app store and the subscription status derived from them. Our server retrieves this status from RevenueCat and records it on your account. We have concluded a data processing agreement with RevenueCat in accordance with Art. 28 GDPR.

To send the emails about your account, we use Resend (Plus Five Five, Inc., 2261 Market Street #5039, San Francisco, CA 94114, USA). Resend receives your email address and the content of the respective email. We have concluded a data processing agreement with Resend in accordance with Art. 28 GDPR.

For the food search and the barcode scan, the app queries the free food database Open Food Facts (Open Food Facts, France) directly from your device. This transmits the search term or the scanned barcode and, for technical reasons, your IP address; no account data is transmitted.

For the gym search, the app queries the public Overpass service (overpass-api.de) directly from your device. It looks up gyms in the free map database OpenStreetMap. This transmits your approximate location and, for technical reasons, your IP address; no account data is transmitted.

Your data is not passed on to advertising partners, data brokers or other third parties for their own purposes. Data is only disclosed to authorities where we are legally obliged to do so.

14. Data transfers to third countries

When the Google services named above are used, data may be processed outside the European Union, in particular in the USA.

The AI features (section 6) are a special case: they are provided through a global endpoint from Google. Your input is processed wherever Google provides the requested model. That can be any country in which Google operates suitable data centers. It is not limited to the USA or the EU. We therefore cannot guarantee a fixed processing region for these features.

For transfers to the USA, we rely on the EU-U.S. Data Privacy Framework (adequacy decision of the European Commission), under which Google is certified. For transfers to other third countries, we rely on the EU Standard Contractual Clauses under Art. 46(2)(c) GDPR, which are part of the data processing agreement concluded with Google.

For subscription management, data is transferred to RevenueCat in the USA. RevenueCat is not certified under the EU-U.S. Data Privacy Framework. This transfer is therefore based on the EU Standard Contractual Clauses under Art. 46(2)(c) GDPR, which are part of the data processing agreement concluded with RevenueCat.

To send the account emails, data is transferred to Resend in the USA. Resend is certified under the EU-U.S. Data Privacy Framework. This transfer is therefore based on the adequacy decision of the European Commission.

15. Retention period

Account and training data is stored for as long as your account exists.

If you delete your account (in the app in your profile under Delete account), your personal data is deleted within 30 days. When you delete it in the app, this happens immediately: the app deletes your training, nutrition and profile data, your form checks with their photos on this device, your username and your account with Firebase Authentication. Our server then automatically deletes your support requests, your reports of published profiles, the counter of your AI usage, the activity log of your account, your customer record at RevenueCat, the photos of your form checks in Firebase Storage and photos that earlier versions of the app stored there. If your account is deleted another way, for example at your request by email, our server deletes all of this data itself. As a guest, you delete your data in your profile under Delete all data, with the same effect.

After that, we keep only a pseudonymous proof of deletion: your former user ID, the time of the deletion and the number of deleted entries, without email address, username or content. It is kept for the standard limitation period of three years (Section 195 of the German Civil Code, BGB) and then deleted automatically.

We keep data on subscriptions and trials for the duration of the contractual relationship. If you delete your account, our server deletes this data as well. A running subscription with the app store does not end as a result. Retention obligations for the purchase receipts lie with the respective app store as the seller.

The hashes kept to protect the sending of emails against abuse (section 3) expire after 24 hours and are deleted automatically afterwards. Resend deletes the sending logs of the account emails automatically after the provider's retention periods.

Crash and diagnostic data is deleted automatically after the provider's retention periods. In line with the AI provider's terms, AI input is only processed for as long as necessary to provide the feature. Support requests are deleted as soon as they are no longer needed, at the latest when the account is deleted, unless statutory retention obligations prevent this.

16. Your rights

Under the GDPR, you have the following rights:

• Access to the data stored about you (Art. 15)
• Rectification of inaccurate data (Art. 16)
• Erasure (Art. 17), directly in the app through account deletion (see section 15)
• Restriction of processing (Art. 18)
• Data portability (Art. 20)
• Objection to processing based on legitimate interest (Art. 21)
• Withdrawal of consent you have given, with effect for the future (Art. 7(3))

To exercise these rights, a message to prover.app.dev@gmail.com is enough.

Right to lodge a complaint: You can lodge a complaint with a data protection supervisory authority, in particular with the authority responsible for the controller, the State Commissioner for Data Protection and Freedom of Information of North Rhine-Westphalia (LDI NRW), or with the supervisory authority where you live.

17. Data security

We take technical and organizational measures to protect your data, including:

• encrypted transmission (TLS/SSL)
• authentication and access restrictions through Firebase security rules
• Firebase App Check: the app's requests to Firebase and to the AI features carry an attestation that they come from a genuine installation of the app. On Android it is generated through Google's Play Integrity API, on iOS through Apple's App Attest.
• an activity log of your account: the type and time of a password change, a requested email change or a data export, without email addresses. These entries are deleted automatically after three years, and immediately when the account is deleted.
• no storage of passwords in plain text
• regular updates

However, absolute security cannot be guaranteed when data is transmitted over the internet.

18. Use by minors

The app is not directed at children under 16. People under 16 may only use the app with the consent of their parents or guardians. We do not knowingly collect data from children under 16 without such consent.

19. Changes to this privacy policy

We update this privacy policy when the law or the features of the app change. We will inform you about material changes in the app. The version published in the app applies.