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Calendarium Solaris

A universal calendar, based on natural rhythms and the cyclical movement of the sun

Privacy Policy

Calendarium Solaris · Last updated: April 2026

1. Who we are

Calendarium Solaris is a calendar project operated under a registered trade name with the Dutch Chamber of Commerce (Kamer van Koophandel). We can be reached at [email protected].

2. What data we collect

We collect the minimum data necessary to operate this website.

  • Account data: If you register, we store your email address and a hashed password. We do not store payment information.
  • Sync data: If you use the sync feature, your calendar data is encrypted on your device before being sent to our server. We store only the encrypted result , we cannot read your appointments, calendar names, or any other calendar content.
  • Encryption salt: A random value used to derive your encryption key is stored on the server alongside your account. This value is not secret and cannot be used to access your data without your password.
  • Usage data: Our server logs standard access logs (IP address, browser type, pages visited, timestamp) for security and diagnostic purposes. These logs are not sold or shared with third parties and are retained for a maximum of 30 days.

3. Apps

The Solaris apps (Calendarium Solaris, Solaris Clock, Solaris Launcher, and Solaris Chat) are currently distributed as beta builds. The following applies to the apps:

  • Calendar app: Uses the same account, sync, and encryption infrastructure as the website. The same data described in section 2 applies. No additional data is collected by the app.
  • Clock and Launcher: These apps operate entirely on your device. No account is required and no data is sent to our servers.
  • Solaris Chat: The chat app uses the Matrix protocol. Messages are end-to-end encrypted between users. The server that processes your messages depends on the Matrix home server you connect to. We are not responsible for data handling by third-party Matrix servers. When using our own Matrix server (if provided), the same privacy standards as this website apply.
  • Beta testing: If you register as a beta tester via the feedback form, we store your email address and the feedback message. This data is used exclusively to coordinate beta testing and is not shared with third parties.

5. Cookies and local storage

This website uses browser localStorage , not cookies , to store your session token after login, your theme preference, and your calendar data locally on your device. If you use the sync feature, an encrypted copy of your calendar data is also stored on our server; the encryption key never leaves your device. No tracking cookies or third-party advertising cookies are used. The only external resource loaded is the Google Fonts stylesheet (Cinzel and Lato), which is subject to Google's own privacy policy.

6. How we use your data

We use the data described above exclusively to:

  • Provide access to registered-user features (document downloads);
  • Maintain the security and availability of this website;
  • Respond to support requests sent to our email address.

We do not use your data for profiling, advertising, or any purpose other than operating this service.

7. Sharing of data

We do not sell, rent, or share your personal data with third parties, except where required by law or necessary to operate the service (e.g. hosting infrastructure). Any such processors are bound by appropriate data processing agreements.

8. Your rights

Under the General Data Protection Regulation (GDPR), you have the right to access, correct, or delete the personal data we hold about you. To exercise these rights, contact us at [email protected]. We will respond within 30 days.

9. Data retention

Account data and your encrypted sync blob are retained for as long as your account is active. You may request deletion at any time. Server logs are deleted after 30 days. Calendar data stored locally in your browser can be cleared via your browser settings.

10. Security

All data is transmitted over HTTPS. Passwords are stored as bcrypt hashes , never in plaintext. Calendar data is encrypted on your device using AES-256-GCM before being sent to our server, meaning we are technically unable to read your appointments. Your encryption key is derived from your password and never transmitted to or stored on our server.

11. Changes to this policy

We may update this Privacy Policy from time to time. The date at the top of this page reflects the most recent revision. Continued use of the website after changes are posted constitutes acceptance of the updated policy.

12. Contact

Questions about this Privacy Policy: [email protected]