Note: This policy describes how Wattstack processes personal data in line with our current technical setup. It is not a substitute for legal advice.
Privacy policy
1. Controller
The controller responsible for processing personal data under the EU General Data Protection Regulation (GDPR) is:
Petermaier Julian (sole proprietor / Einzelunternehmen, Austria)
Schönbrunnerstraße 213-215, Top 412
1120 Vienna
Austria
Email: [email protected]
2. Scope
This privacy policy applies to visits to this website at https://wattstack.jpe-studio.dev and to your installation and use of the mobile application Wattstack (Android).
3. Website hosting and server logs
When you open this website, the hosting provider and/or web server necessarily processes technical data such as IP address, date and time of the request, amount of data transferred, browser type, and, depending on configuration, referrer URL.
Provider / hosting type: This website is deployed with Coolify on a virtual server operated by
Hetzner Online GmbH, located in Frankfurt am Main, Germany (EU/EEA).
Legal basis: Art. 6(1)(f) GDPR (legitimate interest in secure, stable website operation) and, where applicable, Art. 6(1)(b) GDPR if the page supports entering into a contract.
Retention: Server log parameters and duration follow Hetzner’s and our server configuration as described in the provider’s documentation.
Hetzner’s privacy notice: https://www.hetzner.com/legal/privacy-policy
4. Website analytics (Umami, self-hosted)
We use Umami, installed and operated on the same server as this website (self-hosted analytics). It helps us understand aggregated use of the site (e.g. page views, referrers) with a privacy-oriented design. Processing takes place in the EU/EEA (same location as the website: Frankfurt).
Legal basis: Art. 6(1)(f) GDPR (legitimate interest in measuring and improving this small project website). We do not use Google Analytics or similar third-party analytics on this site. You can use browser settings or extensions to limit tracking; if Umami sets or reads storage on your device, you can clear site data in your browser.
5. Android app “Wattstack”
Wattstack displays and monitors battery management systems (BMS) via Bluetooth Low Energy on your device. As a rule, readings and related information are processed and stored locally on your phone (e.g. in a local database) to provide the app (dashboards, history, connection management).
Device access (adjust to the permissions you actually request):
- Bluetooth — to discover and connect to compatible BMS units nearby.
- Location / approximate location — on Android, location permission is often required for Bluetooth scanning; the app does not use it for advertising or location tracking, only where the operating system requires it for BLE scanning.
- Notifications / foreground service — may be needed for a stable connection and ongoing monitoring in the background (e.g. a visible notification while a foreground service runs, as required by Android).
No cloud telemetry from us: We do not operate crash reporting, in-app analytics, or other telemetry that sends your BMS data or usage to our servers. Statistics and diagnostics shown in the Google Play Console are processed by Google as part of the store service; see Google’s privacy policy.
Legal basis: Art. 6(1)(b) GDPR (performance of the app relationship) and, where applicable, Art. 6(1)(f) GDPR (operation, security, troubleshooting) where not covered by (b).
6. Distribution via Google Play
The app is distributed only through the Google Play Store. Google processes data as an independent controller or processor in the context of the store (e.g. account, device, transaction data). Google’s privacy policy applies: https://policies.google.com/privacy
7. Contact by email
If you email us, we process the data you send (e.g. sender address, message content) to handle your request. Legal basis: Art. 6(1)(b) GDPR (steps prior to or under a contract) and/or Art. 6(1)(f) GDPR (responding to inquiries), depending on the subject matter.
8. Retention
We delete personal data when the purpose no longer applies and no statutory retention obligations require storage. You can remove on-device app data by uninstalling the app or clearing app data (per Android settings). We do not maintain separate long-term databases of website visitors or app users beyond what is described in this policy (hosting, Umami, and email handling).
9. Sharing data
We share data with third parties only if needed to perform a contract, we are legally required to do so, you have consented, or we rely on legitimate interests that are not overridden by your rights. Processors in connection with this website: Hetzner Online GmbH (hosting/infrastructure). Messages to our contact address use standard email delivery; we do not use separate CRM or marketing tools for this project.
10. Transfers outside the EU/EEA
The website, Umami, and server logs described above are processed in the EU/EEA (Frankfurt). Google (Google Play, Play Console) may process data in countries outside the EU/EEA; Google describes its safeguards in its privacy policy and related terms. We do not otherwise intentionally transfer your personal data to non-EEA countries for the services we operate ourselves.
11. Your rights
Subject to legal requirements, you have the right to:
- Access personal data we hold about you (Art. 15 GDPR)
- Rectification (Art. 16 GDPR)
- Erasure (Art. 17 GDPR)
- Restriction of processing (Art. 18 GDPR)
- Data portability (Art. 20 GDPR)
- Object to processing based on Art. 6(1)(f) GDPR (Art. 21 GDPR)
- Withdraw consent with future effect, where processing is based on consent (Art. 7(3) GDPR)
To exercise these rights, contact the controller at the email address above.
12. Right to lodge a complaint
You have the right to lodge a complaint with a supervisory authority, in particular in the member state of your habitual residence, place of work, or the place of the alleged infringement.
In Austria, the supervisory authority is the Austrian Data Protection Authority (Datenschutzbehörde).
Website: https://www.dsb.gv.at/
13. Changes
We may update this policy when the law, our services, or app features change. The current version is always available on this page.