Privacy Policy

Last updated: October 18, 2026

Who we are

Fit4i is a personal fitness coaching app for iPhone. This policy explains what data Fit4i collects, why, and what control you have over it. Questions? Email support@fit4i.com.

Data we collect

Account data — your email address, name and password. Passwords are stored only as salted hashes; we never see or store your plain password.
Profile data — age, sex, height, weight, goal, experience level, available equipment, injury areas and activity level. This is what your training and nutrition plan is built from.
Training data — your programs, logged workouts, sets, reps and weights.
Nutrition data — the foods you log and your body-weight entries.
Health data (only with your explicit consent) — heart-rate variability, resting heart rate, sleep stages and duration, steps, active energy and blood oxygen, read from Apple Health or a connected wearable such as Polar. Access is read-only and limited to the types you approve in the permission dialog. Fit4i never writes anything to Apple Health.
Apple Ads attribution (iOS)— when you first sign in, the app asks Apple's AdServices framework for a one-time attribution token and sends it to our server, which asks Apple whether the install came from an Apple Ads campaign. We store Apple's answer — whether the install was attributed and, if so, the campaign, ad group, keyword and ad identifiers, country and the date of the ad tap — linked to your account. The token itself is not stored. This does not use the advertising identifier (IDFA), does not track you across other apps and websites, and needs no tracking permission.
Usage and diagnostics data— events about how you use the app and crash and error reports (see PostHog and Sentry under "Service providers").

Meal recognition

When you log a meal by photo, by nutrition-label photo or by typing a description (Pro), the photo or text is sent to our server and passed to our AI provider, OpenAI, to estimate the foods and macros. The photo or text itself is not stored — it is processed in memory and discarded; it is never saved to our database or linked to your account. Only the food entries you confirm after reviewing the results are saved.

How we use your data

To build and adapt your training program and nutrition targets.
To assess your daily recovery (for example, HRV against your own baseline, sleep duration) and adjust today's recommendation.
To estimate meals from a photo, a nutrition label or a text description, and to write the text of your daily plan (see "Service providers" below).
Apple Ads attribution data is used only to measure which of our ads bring people who actually use the app, so we can spend our advertising budget on what helps. It is not shared with other third parties (apart from RevenueCat, see "Service providers") and not used to target ads to you.

We do not sell your data. We do not use your health data for advertising. We do not track you across other apps and websites.

Service providers (processors)

OpenAI— Fit4i has no AI chat. Our server sends data to OpenAI's API only in these three cases, and only the data listed:
- Meal recognition (Pro) — only when you use it. The meal or nutrition-label photo you take or choose, or the meal description you type, and, for a meal photo or description, your app language.
- Food search translation. If a food search finds too few results, is not in our built-in dictionary and contains letters outside the basic English alphabet (for example Cyrillic, or accented letters such as ä or é) or your app language is German, the search text alone is sent to be translated into English, so we can also search the international food database.
- Daily plan text.When there is recent recovery data — from Apple Health or a connected wearable (from today or yesterday), or today's check-in — our server asks OpenAI in the background to write the text of your daily plan and tip. It sends your app language, that recovery data and the readiness status calculated by our own algorithm, and may add your profile (age, sex, height, weight, goal, experience level, equipment, injury areas, training days per week, dietary preferences, your HRV baseline and which wearable you connected) and a summary of your recent recovery data (HRV, sleep, recovery score, steps) and workouts (dates, exercises, muscle groups, duration). Your readiness status is always calculated by our own algorithm, not by AI. Without recent recovery data, nothing is sent.
We never send OpenAI your name, email address, password, account ID, payment or subscription details, or Apple Ads attribution data.
Railway — hosts our servers and database (US/EU infrastructure).
PostHog (EU) — usage analytics.The app sends usage events to PostHog's EU cloud (eu.i.posthog.com): actions in the app — for example opening it, onboarding steps, starting or completing a workout, adding a food entry — with technical details such as counts, durations, the app version, device model and operating system, and an approximate location that PostHog derives from your IP address. After you sign in, events are linked to your account ID. We never send PostHog your name, email address, password, body measurements, health data or the weights you log. We use it only to understand and improve the app.
RevenueCat — subscriptions. Purchases are made through the App Store; RevenueCat verifies them and tells our server whether your Pro subscription is active. It receives your account ID, your purchase and subscription details and, on iOS, an Apple Ads attribution token so it can tell which of our ads led to a subscription. It does not receive your email address, name or health data.
Sentry (EU) — crash and error reports. When the app or our server hits an error, a report is sent to Sentry, hosted in the EU (Germany): what went wrong and where in the code, the app version, device model and operating system, and a sample of performance measurements. Reports are not linked to your account: we do not attach your name, email address or account ID to them, and Sentry is set not to collect your IP address or the contents of your requests, including health data. In rare cases the text of an error message can itself contain a detail it is about, such as an email address.
Resend — email. If you ask to reset your password, our server sends your email address and the reset link to Resend, which delivers the email. We send no other email through it.
Open Food Facts — a public food database. When you search for a food, the search text (or its English translation) and your app language, without any information about you, may be sent to it, for example when our own food catalog has too few matches.

Health data specifics

Apple Health data never leaves your device without your explicit permission in the HealthKit dialog. You can revoke access at any time in iOS Settings → Privacy & Security → Health. Health data is used exclusively to assess recovery and adapt your training. It is never used for advertising and never shared with third parties. The only processing outside our servers is the daily plan text described under "Service providers": when there is recent recovery data, it is sent to our processor OpenAI to write the text of your plan.

Retention and deletion

Your data is retained while your account is active. You can delete your account — immediately and irreversibly — in the app under Settings → Delete account, or by emailing us from your account address. Deletion erases your profile, programs, workouts, nutrition diary and biometrics, as well as Apple Ads attribution data.

Age

Fit4i is intended for people aged 16 and older. We do not knowingly collect data from anyone younger. If you believe a person under 16 has created an account, contact support@fit4i.com and we will delete it.

Your rights

You can access and correct your data in the app, and delete it as described above. For anything else — including data export requests — contact support@fit4i.com.