Legal
Privacy Policy
Last updated 2 October 2026
Marble is an iPhone app that estimates the nutrition in your meals from a photo and coaches you toward a goal. This page explains what it keeps, what leaves your phone, and how to get rid of all of it.
The short version. There is no account and no sign-up. Your meals, photos, goals and conversations are stored on your iPhone, not on a server. Photos and messages are sent to Anthropic to be analysed and the answer comes straight back — they aren't kept. Nothing is sold, and there is no advertising or tracking of any kind.
What stays on your phone
Marble stores your information in the app's own storage on your device. That includes:
- Your goals — sex, height, weight, activity level, the goal you picked, and the calorie and macronutrient targets calculated from them.
- Your meals — the photos you take, the dish, and its calories, protein, carbohydrate and fat.
- Your weigh-ins — the number and the date, in a file on your device. The list of readings never leaves your phone: the trend, the verdict and every correction to your calorie target are computed here. When you ask the coach about your weight, it sends the computed figures it needs to answer (your trend weight, your weekly rate, the change over the period), not the readings.
- Your conversations with the coach.
- Your settings — theme, and your weigh-in reminder time if you set one.
None of this is uploaded to an account, because there isn't one. You never give Marble an email address, and there is nothing to log in to.
What leaves your phone
Meal photos and coach messages
To read a meal or answer a question, Marble sends that photo or message to Anthropic's Claude API and shows you what comes back. To answer, the coach can ask the app for figures from your log (today's totals, meals that match your question, your targets, your weight trend, your workouts), which are computed on your phone and sent with the conversation. The request is processed to produce your answer and is not stored in a Marble database afterwards. Marble does not use anything you send to train any model.
Web lookups
The coach can search the web and read a page, for example a restaurant's published nutrition. These run through Anthropic's web search on the coach's behalf; the search is about the food or the place, and the pages it read are shown under the answer.
Barcodes
When you scan a package, Marble looks the barcode up on Open Food Facts, a public food database. Only the barcode number is sent — no photo, no identifier, nothing about you.
A random app identifier
Each install generates a random identifier that is sent with those requests so that AI usage can be rate-limited. The only thing recorded against it is a daily count of requests. It is not linked to your name, your email, your device's advertising identifier, or anything you log — and it is gone when you delete the app.
Where to eat
Only when you ask the coach where to eat, Marble asks for your location and sends it to Apple Maps to find restaurants nearby, as any maps app does. Your exact location is not sent to Marble's servers or to the AI. What is sent there is the names and walking distances of those restaurants, your town or city, and what this meal should come to, so the coach can read their menus. Nothing is stored after the answer comes back.
These requests are served through Supabase, hosted in the United States, which passes them to Anthropic. Marble does not collect your contacts or your health records. It reads from Apple Health only if you switch the Activity row in Stats & targets to Health: your workouts and active energy for the last two weeks, used on your phone to set your activity level. Nothing is written to Health.
There are no advertising networks, no data brokers, and no third-party analytics or trackers in Marble. Your information is never sold.
How long it's kept
Your meals and photos stay on your phone until you delete them. Deleting a meal removes that entry and its photo immediately. Because there is no server-side copy, there is no archive to clear out.
Deleting your data
Delete individual meals inside the app, or delete the app to remove everything at once — your goals, meals, photos and conversations all live in the app's own storage and go with it. There is no account to close and nothing left behind on a server.
Children
Marble is not intended for children under 13.
Not medical advice
Marble estimates nutrition and suggests targets. It is not a medical device and does not provide medical advice, diagnosis or treatment. Talk to a doctor or a registered dietitian before making significant changes to how you eat, particularly if you have a health condition or a history of disordered eating.
Changes
If this policy changes in a way that affects what is collected or who it is shared with, the date at the top will change and the app will say so.
Contact
Questions about any of this, or requests about your data: support@getmarble.app