Privacy Policy — Kaern
Last updated: August 2026
1. Data controller
The data controller is Antoine Nion, who publishes Kaern as a personal project. Contact: [email protected].
2. Data processed
Depending on the features you use, Kaern processes:
- your account and Google or Apple sign-in information;
- your profile, goals, preferences, and training constraints;
- activities synced from a sports provider or imported from a file, including duration, distance, elevation, and heart rate when available;
- messages to the coach, session ratings, and generated plans;
- beta access or contact requests;
- limited technical data needed for security, error diagnosis, and, with consent where required, audience measurement.
Some sports information, such as heart rate or data from which physical condition can be inferred, may qualify as health data. You choose whether to provide it or connect a service that sends it. You can withdraw that choice by disconnecting the provider or deleting your account.
3. Purposes and legal bases
Data is used to provide your account, sync activities, build and adapt training, answer requests, secure the service, and fix errors.
Depending on the processing, the legal basis is performance of the requested service; your consent, including for health-related data, the waitlist, and non-essential trackers; our legitimate interest in securing and improving the beta; or a legal obligation. You may withdraw consent at any time without affecting earlier processing.
Kaern does not sell personal data or use connected data to train its own artificial intelligence models.
4. Recipients and technical providers
Only Antoine Nion and providers needed to run Kaern may access the data relevant to their role: hosting, authentication, sports platforms you choose to connect, technical coaching services, error diagnosis, audience measurement, forms, and communications.
You may request the current list of relevant providers by emailing [email protected].
Some providers may process data outside the European Economic Area. Where applicable, Kaern relies on GDPR safeguards such as adequacy decisions or standard contractual clauses.
5. Retention
Account data is kept while you use the service and deleted on request, except for limited retention required by law or needed to defend legal rights. Waitlist data is kept until you unsubscribe or while the project has a valid reason to contact you. Technical logs and backups are retained for a limited period proportionate to security and service continuity needs.
You can delete your account directly in the app. See also Account deletion.
6. Security
Kaern uses reasonable security measures, including encrypted connections, access controls, and limited data access. No system can guarantee absolute security.
7. Your rights
You may request access, correction, deletion, restriction, or portability of your data, object to certain processing, and withdraw consent. Email [email protected]. Identity verification may be required.
You may also lodge a complaint with the CNIL or your local data protection authority.
8. Changes
This policy may evolve with the service. The update date will appear at the top, and material changes will be communicated appropriately.