Privacy Policy
How we handle your health, training and account data, who it is passed to, and what rights you have.
Last updated: October 28, 2026
1. Controller
The controller responsible for processing your data is [NAME], [ADDRESS], reachable at support@muscle-vision.de. For any question about data protection, or to exercise your rights, please contact that address.
2. Local first, then synchronised
Momentum is built local-first. Everything you enter is stored on your device first and works without an internet connection. If you use the app without an account in guest mode, your training, nutrition and body data never leave your device — nothing is transmitted to us. The app only asks whether its version is still supported and whether an update is available (section 11). If you create an account, your data is additionally transferred to our servers so you can use it on several devices and restore it after changing phones.
3. What we process
Account data: email address, password (only ever as a cryptographic hash), language and the verification status of your email address; if you sign in with Apple or Google, instead of the password the identifier Apple or Google uses for you towards us. Profile details: first and last name, date of birth, gender, height, training goals, an occasion and its date, experience, preferred session length, muscle focus and diet, where you provide them. Health and training data: joint complaints and their severity, which generated plans and workouts take into account, what you said about your everyday activity, workouts with exercises, weights and repetitions, body weight and measurements, step counts and manually logged walking distances and a food diary with foods and nutrition values. Usage data: when you made entries, your settings, and the achievements you unlocked.
4. Health data and legal basis
Training, body, step and nutrition data are health data within the meaning of Article 9 GDPR and are specially protected. We process them solely on the basis of your explicit consent under Article 9(2)(a) GDPR, which you give by using synchronisation and can withdraw at any time. Your account data is processed to perform the user agreement under Article 6(1)(b) GDPR. Withdrawing consent does not affect the lawfulness of processing carried out beforehand; you can continue using the app in guest mode without any transmission. Momentum is intended for people aged 16 and over, the age from which you can consent to the processing of health data yourself (Article 8 GDPR). If we learn that an account belongs to someone younger, we delete it together with its data.
5. Where your data is stored
Your account, the database and uploaded images are held at Supabase, operated by Supabase Inc. The project server is located in the [REGION] region. Synchronisation between your devices runs through PowerSync Cloud (Journey Mobile, Inc., USA) on servers in the EU; any transfer to the USA is based on standard contractual clauses. Our website is served by Cloudflare. Emails we send you – to confirm your address, to reset your password, and notices about changes to the terms or this privacy policy – are sent through Resend (Resend, Inc., USA). This transfers your email address and the content of the message; the transfer to the USA is based on standard contractual clauses. Data processing agreements under Article 28 GDPR are in place with all of these providers. If you sign in with Apple or Google, Apple (Apple Distribution International Ltd., Ireland) or Google (Google Ireland Limited) confirms your identifier and your email address to us with a sign-in token – with Apple, if you choose, a relay address that hides your real one. We do not request your name there. When you register with Google, we take your Google profile picture once as your profile picture if you set your own picture at Google and none in Momentum yet; for this we ask Google about it, download the picture from Google once and store a copy with us. You can change or remove it in the settings at any time. Apple provides no profile picture. The legal basis is the performance of the user agreement under Article 6(1)(b) GDPR. If you delete an account that signs in with Apple, we revoke that sign-in at Apple; for this we send Apple a one-time code from your renewed sign-in. Apple and Google are responsible for the sign-in itself as independent controllers; their privacy policies apply.
6. Apple Health and Health Connect
If you enable the health connection, the app reads step and activity data from Apple Health or Health Connect. It also writes the workouts you log in Momentum, including their estimated energy, your weight entries and your height into it. It also writes manually logged steps and walking distances, as well as your body fat entries, to Apple Health, including the estimate confirmed during onboarding. If you change or delete such an entry in Momentum, it is changed or deleted there as well; only the device on which the entry was created writes it. Completed days are cached so that a second device can show the same figures. You decide in the system settings which data may be read and written, and you can disconnect there at any time. Entries already written stay in your health store until you delete them there.
7. Food search and barcodes
When you search for a food that is not held on your device, or scan a barcode, the app queries the public Open Food Facts database. The search term or barcode and your IP address are transmitted to Open Food Facts. No link to your account is made. The scan itself happens on your device; the camera image is not transmitted.
8. AI features: photo recognition and coach
If you use photo recognition, the picture you take is transmitted to OpenAI (OpenAI, L.L.C., USA) to estimate the foods and amounts visible in it. OpenAI stores the image temporarily for abuse detection and does not use it to train AI models; we do not store it ourselves. The transfer to the USA is based on standard contractual clauses. Please make sure the photo does not show people whose data you do not want to transmit. The feature is optional: it only runs after your explicit consent (Art. 9(2)(a) GDPR), which we store with its time and which you can withdraw at any time in the settings, and only when you take a photo. If you use the coach, the app transmits your recent messages with each message, together with a summary created on your device, to OpenAI: your goals and profile answers from onboarding, the training days and exercises of your active plan, the names of your own exercises, your scheduled workouts, how often you train, your weekly goal and records, your last ten finished workouts with their exercises, sets, weights and repetitions, how your training weights developed per exercise with an estimated maximum, your body weight and its trend, the latest value of each of your body measurements, your average daily steps over the last 30 days, the equipment of your active gym, your nutrition targets and the averages of your logged days, the foods and meals you logged in the last seven days with their calories and protein, the water you logged today, and the length of your streaks – no notes. Because this is health data, it only happens with your explicit consent (Art. 9(2)(a) GDPR), which we store with its time and which you can withdraw at any time in the settings. OpenAI stores the requests temporarily for abuse detection and does not use them to train AI models. So that OpenAI can reuse the parts of your requests that stay the same, it also receives a pseudonymous identifier derived from your account, but not your account id or email address. We store your chats with the coach on our server (Supabase) so they are available on all your devices, together with the changes the coach proposes to you (such as a food diary entry or a plan change) – a proposal is only carried out when you confirm it in the app, and then on your device; we delete each chat six months after its last message – a chat you mark to keep for good only when you delete it –, immediately when you delete it, and all of them when you withdraw your consent. If you additionally switch on the coach's memory – it is off unless you switch it on – we store short notes the coach takes about you from your chats (such as preferences or limitations) on our server and transmit them to OpenAI with each message as well; you can delete each note on its own in the settings, and we delete all of them when you switch the memory off or withdraw your consent. We only count how many messages you send per day in order to enforce the daily allowance. The coach requires an account.
9. Content you share with others
Some features are public by design. If you create a share link for a plan, an exercise or a workout, that content is retrievable by anyone who has the link. Anyone opening the link sees your first name on our website and whether it is a plan, an exercise or a workout; the content itself is only shown in the app. If you create a food and do not mark it as private, it is proposed for the shared catalogue. It is only published once we have reviewed the entry; until then it may be shown to people who create the same food themselves. What is visible is the name, brand and nutrition values, but not who created the entry. If you report an incorrect catalogue entry, we store your report together with your account id so we can follow up on it. If you send us feedback – a bug or a feature wish, from the settings or as a draft by the coach that you send yourself – we store it with your account id, the app version and the operating system version so we can follow up on it and work on it. With an account you can add friends: a friendship only starts from your personal invite link, which you pass on yourself, and takes effect once the other person accepts it in the app. Anyone opening the link sees only your first name on our website. Your friends see your first and last name, profile picture, optional bio, the length of both streaks (nutrition and training) and the three totals at the top of your profile (completed workouts, active days and days with food logged). For this the app transmits the streaks’ length, the day through which they remain valid without further activity, and these three numbers. Individual workouts, training statistics, achievements earned, notes, meals, body measurements and weekly goal are not shared with friends. The invitation and acceptance screens explain what becomes visible before the friendship starts. You can change your names and bio, or remove your bio, in profile settings. Under My friends → You, you can see your friend profile the way your friends see it. Removing a friend ends the friendship and mutual profile access for both people and renews your invite link.
10. Error diagnostics
If the app crashes or an error occurs, we transmit a technical error report to Sentry (Functional Software, Inc.), processed in the EU. Such a report contains the error, the place in the program, the device model and app version, and your pseudonymous account id, so we can tell whether one error keeps hitting the same person. Your email address, name, IP address and your health or nutrition data are not transmitted; search terms and content are stripped before sending. The legal basis is our legitimate interest in a working app under Article 6(1)(f) GDPR.
11. App updates
At launch and whenever you return to the app, it asks our server (Supabase) whether its version is still supported. Only the request itself and your IP address are transmitted, no account, health or nutrition data. The app also checks at launch whether an update is available for it and downloads it if so. For this we use EAS Update by Expo (650 Industries, Inc., USA). Your IP address, the platform, the app and runtime version, the id of the installed update and a random installation id are transmitted; the app creates that id itself and it has no connection to your account. The transfer to the USA is based on standard contractual clauses. Both also happen in guest mode. The legal basis is our legitimate interest in fixing errors quickly and in not leaving an app version running that no longer works with our servers, under Article 6(1)(f) GDPR.
12. Momentum Pro purchases
A subscription is handled by the App Store or Google Play. We receive no payment data. The purchase and the check whether it is valid are handled through RevenueCat (RevenueCat, Inc., USA). For this the app sends the store's purchase receipt, a random identifier and, once you have an account, your account ID to RevenueCat; RevenueCat checks the purchase with Apple or Google, and we store the result against your account. If you buy without an account, RevenueCat knows only the random identifier; if you create an account later, the purchase is assigned to it. The transfer to the USA is based on standard contractual clauses.
13. Retention
We keep your data for as long as your account exists. If you delete your account, your personal data and your uploaded images are deleted. Foods already published in the shared catalogue remain, without any link to you, because other users rely on them in their diaries. Error reports are deleted automatically after 90 days.
14. 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). You can produce a complete, machine-readable copy of your data yourself at any time: in the app under Settings → My data → "Export my data". You can also delete your account yourself in the settings. For anything else, reach us at support@muscle-vision.de. You also have the right to lodge a complaint with a data protection supervisory authority.
15. Changes to this privacy policy
When our processing changes, we update this policy; the date at the top shows when. Material changes – such as a new processor, new types of data, new purposes or longer retention – are shown to you in the app beforehand and, if you have an account, also sent to you by email. Pure corrections and clarifications without a change in substance are not announced separately. Where processing relies on your consent and a change goes beyond what you consented to, we ask you again; until then the extended processing does not take place.