Privacy Policy

This Privacy Policy explains how Marble (“Marble”, “we”, “us”) handles your information when you use the Marble mobile application (the “App”) and this website. Marble is a fitness app that helps you track nutrition and training and uses AI to analyse your physique, your meals and your progress.

Marble is designed to be private by default. In short:

• There is no account and no sign-up. We do not collect your name, email address or password.
• Your profile, logs, history and photos are stored on your device. AI requests use temporary server storage as described in sections 3 and 10.
• AI features send only the data needed to produce your result, after you agree. Photos and other request inputs are deleted when processing finishes. Results are deleted after your device confirms saving them, with automatic expiry if confirmation cannot be delivered (section 10).
• We use no advertising and no cross-app tracking, and we do not sell or share your personal information for advertising. The App sends anonymous usage events and crash reports to a product-analytics provider so we can find bugs and see which features are used (section 8).

1. No accounts — an anonymous identifier

When you first open the App, it generates a random identifier and stores it in your device’s secure storage (iOS Keychain / Android Keystore). This identifier is not derived from and cannot be linked to your name, email address, phone number or any other real-world identity. It is used to manage your subscription (as your customer ID with our payment partner), enforce fair-use limits, retrieve and delete your AI job results, and associate the usage events described in section 8.

2. Information stored on your device

The following information is collected in the App and stored locally on your device. It is not uploaded to our servers, except for the specific AI-feature data flows described in section 3.

• Profile: your name (used only to address you in the App — it never leaves your device), sex, date of birth, height, weight, activity level, motivations, dietary preferences (which may include religious dietary patterns such as halal or kosher), training obstacles, and an optional free-text notes field (for example injuries, allergies or schedule constraints).
• Goals and targets: goal type, target weight and date, calorie, macronutrient, water, step and training targets.
• Logs: weight history, meals and nutrition entries, workouts, weekly check-ins, chat history with the coach, and app settings.
• Photos: body and progress photos, meal photos, custom exercise photos and plan cover images, stored in the App’s private storage on your device.

3. Information sent when you use AI features

AI features require sending certain data from your device to our backend, which forwards it to the AI providers listed in section 4. Each feature sends only what it needs:

• Physique scan: the body photo you choose, basic stats (age, sex, height, weight, goal, training experience) and numeric body-pose measurements computed on your device.
• Future body render: the body photo you choose and your basic stats, used to generate an AI-edited image estimating your future physique.
• Meal analysis: the meal photo or description you submit, your dietary preferences and your profile notes.
• Training plans: your basic stats, training preferences and profile notes.
• Weekly check-in: aggregated statistics from your week (weight trend, calorie averages, logging streaks, sessions completed).

Photos and other AI request data are transmitted over encrypted connections. For meal analysis and body scans, our backend temporarily stores the request inputs so processing can continue if you close the App or lose your connection. Uploaded photos and the other stored inputs are deleted when processing finishes, whether it succeeds or fails. Results and generated images remain available for recovery until your device confirms saving them or the request expires, as described in section 10. We do not use your photos or data to train AI models. Your free-text profile notes accompany meal analyses, plan requests and check-ins, so avoid putting anything in the notes field you would not want processed by our AI providers.

Before a body photo is analysed, it is screened on your device using Apple’s Sensitive Content Analysis, and again by our backend; explicit imagery is blocked and never rendered.

Your consent. Nothing in this section is sent until you agree. The first time you use an AI feature, the App shows you what that feature sends and which providers receive it, and asks for your permission; if you decline, no AI request data is sent and the rest of the App keeps working. You can withdraw this permission at any time in Settings › AI features, which turns the AI features off without affecting your tracking, your own plans or Apple Health.

4. Service providers

We use a small number of service providers to run Marble. Each receives only the data needed for its function, under terms that limit its use to providing the service. We only work with providers that are contractually required to protect your data to the same or an equal standard as this policy, and none of them may use your data for their own purposes, for advertising, or to train AI models:

• Convex — hosts our backend, which relays AI requests, temporarily stores AI job inputs and results as described in section 10, and stores the anonymous subscription and usage records described in section 8.
• OpenRouter — routes AI requests to the underlying model provider.
• Google (Gemini models) — the AI models that currently analyse photos and generate results, accessed through OpenRouter. The specific model provider may change as we improve the App.
• Exa — a web search service used during meal analysis to look up nutrition information; it may receive search queries derived from your meal description, never your photos.
• RevenueCat — manages subscriptions. It receives your anonymous identifier and purchase receipt data from Apple. We never see your payment card details.
• Apple — processes payments through the App Store, provides on-device photo screening, and (if you use voice logging) speech-to-text, described in section 6.
• PostHog — product analytics and crash reporting, hosted in the European Union. It receives the anonymous usage events and crash reports described in section 8, never your photos, logs or profile content.

5. Apple Health

If you enable health sync, Marble reads your step count, active energy and workouts from Apple Health to enrich your check-ins. This access is read-only — Marble never writes to Apple Health — and you can turn it off at any time in Settings. We do not use Apple Health data for marketing or advertising, and we do not share it with third parties, in accordance with Apple’s HealthKit guidelines.

6. Voice input

If you log meals by voice, the App uses your device’s speech recognition (provided by Apple on iOS). Depending on your device settings, audio may be processed on Apple’s servers to produce the transcription, under Apple’s own privacy policy. Marble only receives the resulting text.

7. Payments

Subscriptions are purchased through the Apple App Store (or Google Play on Android) and managed by RevenueCat. Payment is handled entirely by the app store under its own terms and privacy policy; we never receive your card number, billing address or other payment credentials.

8. Service records we keep

To operate fair-use limits and prevent abuse, our backend keeps records of AI feature usage keyed to your anonymous identifier: which feature was used, which model served it, token counts and processing cost, timestamps, and error messages when a request fails. These records contain no photos and no profile content, and cannot be linked to your real-world identity by us.

Usage analytics and crash reports.The App also sends anonymous product-analytics events to PostHog, keyed to the same anonymous identifier. These are collected automatically by the analytics library as you use the App and consist of: which screens and features you use (for example that a body scan was started, a meal was logged, a plan was generated or a workout was completed), simple counts attached to those events (such as the number of items in a meal or sets in a workout), whether an AI request succeeded or failed and why, whether you hold a subscription, app open and close events, and crash reports containing technical error details. Each event also carries your device model, operating system version, app version, language and screen size. Events never include your name, your photos, meal descriptions, notes, weights, measurements, chat messages or Apple Health data. We use this information only to fix bugs, understand which features are used and improve the App; it is not used for advertising or shared with anyone else.

9. What we do not do

• No advertising, attribution or cross-app tracking SDKs, and no advertising identifiers (IDFA). The only third-party analytics is the anonymous usage and crash reporting described in section 8.
• No selling or sharing of personal information for advertising.
• No collection of your location, contacts, or browsing activity.
• No push notifications — reminders are scheduled locally on your device, and are off by default.
• No social features — nothing you log is visible to other users. If you share a progress photo, it goes through your device’s share sheet at your explicit request.

10. Data retention and deletion

Because your data lives on your device, you are in direct control of it. In Settings, Reset account permanently erases all Marble data on your device, including every photo, log and profile field. Deleting the App removes its local data as well.

For meal analyses and body scans, uploaded photos and other job inputs are deleted as soon as processing finishes or a failed job is settled. Results, including generated images, are deleted when the App confirms that they have been saved on your device. If the App cannot send that confirmation, it retries when it is opened with a connection. As a fallback, automatic deletion is scheduled for 24 hours after the request was created; an hourly cleanup also removes expired jobs and settles interrupted processing. Older App versions that do not send confirmation rely on this expiry.

Separately, the anonymous subscription and usage records described in section 8 are kept as long as needed to operate the service, enforce fair-use limits and meet legal obligations. To request deletion of these records, contact us at contact@getmarble.fit.

11. Security

Your anonymous identifier is stored in your device’s secure storage, local data is held in the App’s private sandbox, and all network traffic uses encrypted connections (TLS). No method of transmission or storage is completely secure, and we cannot guarantee absolute security.

12. Children

Marble is not intended for children under 16, and the App does not accept a profile age below 16. We do not knowingly process data of children under 16; if you believe a child under 16 has used the App, contact us and we will delete any associated server records.

13. Your rights

Depending on where you live (for example under the GDPR in the European Economic Area and the United Kingdom, or the CCPA in California), you may have rights to access, correct, delete, restrict or object to the processing of your personal data, to data portability, to withdraw consent, and to complain to your local data protection authority.

You can manage your local profile, logs and photos in the App and erase them via Reset account. This local reset does not itself delete server records; temporary AI jobs follow the deletion schedule in section 10. For anything else — including deletion of server-side records — contact us at contact@getmarble.fit and we will respond within the timelines required by applicable law. We will never discriminate against you for exercising your rights.

14. International transfers

Our backend and AI providers process data in the United States and other countries which may have different data-protection laws than your country. Where required, transfers are protected by appropriate safeguards such as standard contractual clauses entered into by our service providers.

15. Changes to this policy

We may update this Privacy Policy from time to time. The effective date at the top reflects the latest revision, and material changes will be communicated in the App or on this website before they take effect.

16. Contact

Questions or requests about this policy or your data: contact@getmarble.fit