Privacy Policy
This policy covers the website isntfunny.de and the Android app DELTA (package de.tecfriends.delta).
Last updated: 4 August 2026
1. Controller
The controller responsible for the processing of personal data described here is:
Sebastian Reuther
c/o Impressumservice Dein-Impressum
Stettiner Str. 41
35410 Hungen
Germany
Email: info@isntfunny.de
Phone: 0157 9234 1658
2. The app DELTA
DELTA reads sleep data from Health Connect and turns it into charts and statistics.
Your data never leaves your device. There is no server, no account, and no third party who can see your data — including us. This is enforced technically, not just promised: DELTA does not declare the android.permission.INTERNET permission. Without it, Android does not allow the app to open any network connection at all. You can verify this yourself in your device's app permission settings.
As a direct result, DELTA contains no analytics, no advertising, no crash reporting, and no tracking of any kind, and it shares no data with anyone.
What DELTA processes, all stored locally:
- Sleep records from Health Connect — start and end times, sleep stages, and which app or device originally recorded them. Access is read-only; DELTA never writes back to Health Connect.
- Optional profile — year of birth and sex, used solely to pick the age-appropriate clinical reference ranges. Both are optional.
- Settings — your sleep goal and whether notifications are enabled.
- Derived metrics — values calculated from the above and cached so charts do not have to be recomputed on every launch.
Legal basis: Sleep data is health data under Art. 9(1) GDPR. Processing rests on your explicit consent under Art. 9(2)(a) together with Art. 6(1)(a) GDPR, which you give by granting access in Health Connect. You can withdraw it at any time by revoking that permission or clearing your profile in the app.
Permissions and why they are needed:
health.READ_SLEEP— the basis for every analysis.health.READ_HEALTH_DATA_HISTORY— without it Health Connect only returns the last 30 days, which is not enough for long-term trends.health.READ_HEALTH_DATA_IN_BACKGROUND— for the once-daily sync, so new nights are ready when you open the app.POST_NOTIFICATIONS— for the daily summary. Notifications are generated locally; no push service is involved. Can be switched off in settings.RECEIVE_BOOT_COMPLETED— re-schedules the daily sync after a reboot, app update, or timezone change.
Data you export yourself: DELTA can produce a PDF report, share a chart as an image, and write a full backup of its database to a location you choose. All three are triggered only by you, and you pick the destination. Once a file is handed to another app or a cloud service, that provider's privacy policy applies. Note that a backup contains your complete sleep history. You can also import a Google Takeout archive; this too is processed entirely on-device.
Retention and deletion: Data stays as long as the app is installed. Uninstalling the app, or clearing its storage in Android settings, deletes everything permanently. We hold no copy anywhere.
Not a medical device: DELTA is not a medical device. Its analyses and reference ranges are informational and do not replace medical diagnosis or treatment.
3. The website isntfunny.de
Server logs: The web server records the requested address, date and time, amount of data transferred, HTTP status, referrer, user agent, and IP address. This is required to deliver the site and to keep it secure and working. Legal basis: Art. 6(1)(f) GDPR — our legitimate interest in a stable and secure service. Log data is deleted no later than 14 days after it is recorded and is not combined with any other data source.
Hosting and DNS: The site runs on a server we operate at netcup GmbH, Emmy-Noether-Straße 10, 76131 Karlsruhe, Germany, in a data centre located in Germany, under a data processing agreement pursuant to Art. 28 GDPR. DNS is provided by Cloudflare, Inc., 101 Townsend St, San Francisco, CA 94107, USA, which resolves the domain name only — site traffic is not routed through Cloudflare.
Cookies: Only strictly necessary cookies are used. There is no analytics, no tracking, and no profiling. Two cookies exist: isntstack_session keeps you signed in, and XSRF-TOKEN protects forms against cross-site request forgery. Both last two hours. Legal basis: § 25(2)(2) TDDDG together with Art. 6(1)(f) GDPR; no consent is required for strictly necessary cookies. This page and the Terms and Contact pages are served entirely without cookies unless you are already signed in.
Account: Accounts exist only for site administration and are not open to public registration. Stored: display name, email address, and the password as an irreversible hash. Legal basis: Art. 6(1)(b) GDPR.
Contact by email: If you write to us, we process your message to answer it (Art. 6(1)(f) GDPR, or Art. 6(1)(b) for contract-related enquiries) and delete it once handled, unless statutory retention periods apply.
The site is served over TLS (HTTPS) only; plain HTTP requests are redirected automatically.
4. Your rights
You have the right to access your data (Art. 15 GDPR), to rectification (Art. 16), erasure (Art. 17), restriction of processing (Art. 18), data portability (Art. 20), and to object to processing (Art. 21). You may withdraw any consent at any time with effect for the future (Art. 7(3) GDPR). An informal message to the address above is enough.
You also have the right to lodge a complaint with a supervisory authority (Art. 77 GDPR), in particular in the country of your habitual residence. The authority responsible for us is:
Der Hessische Beauftragte für Datenschutz und Informationsfreiheit
Postfach 3163
65021 Wiesbaden
Germany
Phone: +49 611 1408-0
Email: poststelle@datenschutz.hessen.de
5. Changes
We update this policy when the processing described here changes or the law requires it. The version published on this page is the one that applies.