Cookie Policy

This Cookie Policy explains what cookies and comparable browser-storage technologies are, which of them HealthSync uses on healthsync.itsmarian.dev, why they are used, and how you can manage your preferences. HealthSync is part of itsmarian's projects.

It should be read alongside the Privacy Policy, the Terms of Use and, where AI features are concerned, the AI Guidelines, which together govern your use of HealthSync.

By continuing to use HealthSync, you confirm that you have read and understand this Cookie Policy. Non-essential cookies are only set after you give explicit consent through the cookie banner. You can update your choices at any time using "Change Cookie Preferences" in the footer of any page.

Last updated: 18 June 2026

Cookies are small text files stored on your device (e.g. computer, smartphone or tablet) when you visit a website. They allow the website to recognise your device on future visits and remember information such as your language preferences or login status.

When you first open HealthSync, the web server can send a cookie to your browser, which stores it locally. On subsequent visits, your browser sends the cookie back to the server, allowing HealthSync to recognise you and keep your session active. Cookies do not contain executable code and cannot access other data on your device.

HealthSync is a Progressive Web App. In addition to cookies, it uses your browser's localStorage to keep your food, drink and workout entries available even when you are offline, and to remember UI preferences such as the active theme. Browser storage that is strictly necessary to provide the service you have actively requested (offline functionality, remembering your last entries) does not require consent under § 25 TDDDG / ePrivacy Directive. For full details, see the Privacy Policy.

Cookies fall into two categories based on how long they are stored:

• Session cookies: Temporary and deleted automatically when you close your browser. Used to maintain your session while you navigate HealthSync.
• Persistent cookies: Remain on your device after your browser is closed, for a defined period of time. Used to remember your preferences or to keep you signed in across sessions.

HealthSync deliberately keeps the number of cookies and trackers small. The following categories apply:

• Strictly necessary: Required for the basic operation of the app and cannot be disabled. This includes the secure authentication cookies set by our backend provider (Supabase) once you sign in. Without these, you cannot stay signed in or synchronise your data across devices. Legal basis: legitimate interests (Art. 6(1)(f) GDPR) and the strictly-necessary exemption under § 25(2) TDDDG.
• Preference and personalisation: Remember UI choices such as the active theme, the last opened view and your onboarding state. These are kept in your browser's localStorage on your device and do not leave it unless you also enable cloud sync.
• Analytics and statistics (consent required): We use Google Analytics 4 to understand in aggregated and pseudonymous form how HealthSync is used (e.g. which views are most popular). Google Analytics is initialised with Google Consent Mode v2 and defaults to denied for every storage category. Cookies are only set after you grant consent in the cookie banner. Legal basis: consent (Art. 6(1)(a) GDPR).
• AI feature flag (only if you opt in): When you enable AI Detection in the settings, your opt-in flag and your personal Gemini API key are stored locally in your browser's localStorage and never in a cookie. They are sent only directly to Google when you actively trigger an AI request. See the AI Guidelines for details.

HealthSync does not serve third-party advertising and does not currently use any advertising or marketing cookies. Should this ever change, this Cookie Policy will be updated accordingly and your consent will be sought before any such cookies are placed.

The use of cookies on HealthSync is governed by applicable data protection law, in particular the General Data Protection Regulation (GDPR) and the German TDDDG. Strictly necessary cookies are used on the basis of our legitimate interest in operating a functional and secure service (Art. 6(1)(f) GDPR) and the statutory exemption under § 25(2) TDDDG. All other cookies are placed only on the basis of your explicit, freely given consent (Art. 6(1)(a) GDPR), which you may withdraw at any time.

You can review and change your cookie preferences at any time by clicking "Change Cookie Preferences" in the footer of any page of HealthSync.

You may also manage or delete cookies directly through your browser settings. Most browsers allow you to block or delete cookies, and to be notified when a cookie is set. Please note that disabling strictly necessary cookies may break sign-in and cloud synchronisation. The following links provide guidance for common browsers:

• Google Chrome: https://support.google.com/chrome/answer/95647
• Mozilla Firefox: https://support.mozilla.org/en-US/kb/cookies-information-websites-store-on-your-computer
• Microsoft Edge: https://support.microsoft.com/en-us/microsoft-edge/delete-cookies-in-microsoft-edge-63947406-40ac-c3b8-57b9-2a946a29ae09
• Apple Safari (macOS): https://support.apple.com/en-gb/guide/safari/sfri11471/mac
• Apple Safari (iOS): https://support.apple.com/en-gb/HT201265

In addition to cookies, you may clear HealthSync's localStorage at any time via your browser's "Clear site data" option or by signing out from within the app. Clearing local data removes offline copies of your entries, your active theme and your onboarding state. Cloud-synced data is not affected and can be retrieved again by signing back in.

For full details on how personal data is collected, processed and stored in connection with cookies and other technologies, please refer to the Privacy Policy. If you have any questions about this Cookie Policy, you may contact us at support@itsmarian.dev.