Privacy Policy
Last updated: 12 October 2026 ·Deutsche Fassung (the German version is authoritative)
Who is responsible?
Kilobook (in German-speaking countries: Hantelbuch) is a private, non-commercial project. Anyone can sign up in the iPhone app; on the website you need an invitation. The controller for the processing of your data is Pascal Schulth, reachable at [email protected].
Website, iPhone app and Apple Watch
Kilobook is available as an app for iPhone and Apple Watch and as a website (hantelbuch.pages.dev). All of them use the same account and the same data. This policy covers all three.
What data is stored?
- Account: first name, email address and your password (only as an encrypted hash that nobody can read).
- Training: training plan, saved plans (“My plans”), weights, sets and reps, exercise notes and equipment settings (such as seat height) and settings such as vacation or deload weeks.
- Complaints (optional): joints where you have complaints (shoulder, elbow, wrist, lower back, knee, hip), if you enter them in the questionnaire or in the plan. They only control which exercises the plan generator suggests and which ones are listed last when you swap an exercise. They are never sent to the AI and never shared in the group. You can change them in the plan at any time or set them to “None”.
- Nutrition: meals, nutrition values (calories and macros and, where known, fiber, sugar, salt and saturated fat), recipes (for recipes you import from a link, also the link to the source), scanned products, water, fasting times and what the app has learned about your eating habits.
- Body: body weight, body measurements, calories burned, steps and progress photos, if you enter them or import them from Apple Health.
- AI usage: for your daily limit and for troubleshooting, the server stores the time, number and model of your AI requests, but not their content.
- Sign-up without an invitation: to prevent mass account creation, the server counts per day how many accounts are created from one IP address. It only stores an irreversible hash of the IP address, the date and a secret random value, never the IP address itself. Entries from previous days are deleted at the next sign-up.
Information about weight, body measurements, nutrition and complaints can be health data. We process it only because and to the extent that you explicitly consented when you signed up (Art. 6(1)(a) and Art. 9(2)(a) GDPR). You can withdraw your consent at any time by deleting your account.
On your iPhone and Apple Watch
The app stores on the device: your sign-in token (in the keychain), a workout in progress, changes that have not been sent yet and a copy of your data so the app also works offline. Widgets on the Home Screen and Lock Screen and the complication on your watch face get the day's values only through the device's storage. The Apple Watch receives your current workout, rest timer and water directly from the iPhone, not over the internet. Reminders are notifications on the device. When you sign out, this data is removed from the device.
Apple Health (optional)
Only if you turn it on in the app, Kilobook reads your active calories, steps and, if you choose, your weight from Apple Health, and writes your strength workouts and your weight to it. Imported values are stored in your account like values you entered yourself. The app also reads your heart rate to show its average and maximum after a workout and, if you turn on "Sleep and recovery", your sleep, heart rate variability (HRV), resting heart rate and VO2 max. It shows these values only on the device; they are not stored in your account and not sent to the server. If you record a workout with the Apple Watch, the watch saves it with heart rate and calories directly to Apple Health. Data from Apple Health is never sent to the AI, never used for advertising and never shared with third parties. You control access in the iPhone Settings under Health.
Who processes the data?
- Cloudflare runs the website, the app's server and the database. The database is located in a European data center. Requests pass through Cloudflare's global network.
- AI providers: Anthropic (Claude) normally handles your AI requests. If Claude is unavailable or its quota is used up, Google (Gemini) takes over for accounts with an invitation and Cloudflare Workers AI for accounts without one. Older app versions whose consent doesn't mention Anthropic yet only use Google or Cloudflare. If the first provider doesn't answer or declines the request, the same request goes to the next one; otherwise only one provider receives it.
- Anthropic (Claude), Anthropic PBC in San Francisco (USA), receives the same content as described below for Google (Gemini) when you use an AI feature and have agreed to it, never including Apple Health values. According to Anthropic, it does not use content from its API to train its models and deletes it within 30 days, unless it has to be kept longer to enforce its usage policy or for legal reasons. The transfer to the USA is based on the European Commission's Standard Contractual Clauses in Anthropic's data processing addendum.
- Google (Gemini) steps in for accounts with an invitation when Claude is unavailable, and only receives data when you use an AI feature and have agreed to it in the app: for "Calculate with AI", your description of the meal, attached photos and the eating habits the app sends along; for a photo of a nutrition label, the photo; for importing a recipe from a link, the link and the content of the recipe page (name, servings and ingredients, or the cleaned-up page text if the page has no recipe data); for the AI coach, your question and a summary of your plan, your recent workouts, your food and your weight trend; for the plan check, your training plan, the number of workouts in the last four weeks and which exercises have stalled; in each case without any Apple Health values. Kilobook currently uses the free tier of Gemini. Under its own terms, Google may use content from this tier to improve its products. Therefore, please don't upload photos in which people can be recognized. You can withdraw your consent in the app under Account › AI features.
- Cloudflare Workers AI processes the same content as described above for Gemini for accounts without an invitation, when you use an AI feature and have agreed to it. The models (for example Gemma) run on Cloudflare's servers; the content is not sent to Google. According to Cloudflare, it does not use the content to train models and does not store it permanently.
- Open Food Facts only receives the barcode number when you scan a barcode and only the search term when you search for food, no information about you.
- Recipe pages: when you import a recipe from a link, the Kilobook server fetches the page. The operator of the page sees a Cloudflare address, not your IP address. The content of the page is not stored, only the recipe you save afterwards.
- Resend sends emails when you use "Forgot password" (your email address and a link) and notifies the admin about reports in the group.
- Other Kilobook users can see a product that you add yourself because it isn't in any database (name, brand, barcode, nutrition values). Who added it is not stored.
Group (optional)
Only if you join the group can other members see: your first name, the names of your workouts, the number of sets, the volume, the duration, new personal records (exercise, weight and reps), your streak, shared plans and your kudos and comments. Nutrition, body weight, measurements and photos are never shared. If you leave the group, nobody can see your posts anymore. When you delete your account, they are removed.
You can report other members' posts and comments and block members. A report stores who reported what, the reported content and the reason until the admin has reviewed it. You no longer see blocked members.
Cookies and tracking
The website uses exactly one cookie, which keeps you signed in. The website and the app contain no advertising, no analytics tools and no tracking.
How long is data stored?
Until you delete entries or your account. When you delete your account, all your data, photos, group posts, reports and blocks are removed immediately.
Your rights
You can request access, rectification, erasure, restriction and data portability at any time. You can export your data (full backup as JSON; workouts, nutrition and body data as CSV spreadsheets) on the website under Account, and the CSV spreadsheets also in the app under Account › Export data. You can delete your account on the website under Account or in the app under Account › Delete account. You also have the right to lodge a complaint with a data protection supervisory authority.