Privacy Policy

Siefken Calendar · Effective September 24, 2026

Siefken Calendar is a private, self-hosted application used by a single family. This policy explains what data it handles and how, primarily so the Google account holder can make an informed decision when authorizing calendar access.

What the application accesses

With the account holder's authorization, the application uses the Google Calendar API (scope https://www.googleapis.com/auth/calendar) to create, update, and delete events on calendars owned by the family's Google account. It does not access Gmail, Drive, Contacts, or any other Google service through the API.

What data is processed

Emails and images that a family member deliberately forwards to the family calendar address. From these the application extracts event details: title, date and time, location, which family member it concerns, and short notes such as "bring cleats". The sender's email address is used to decide whether to trust the message and where to send the confirmation reply.

Where data is stored

All processing and storage happen in a cloud account owned and controlled by the family (Amazon Web Services). Forwarded messages are retained for up to 90 days and then deleted automatically. Extracted event records are kept in a private database so the application can detect duplicates and apply updates. Google Calendar holds the resulting events, exactly as if they had been entered by hand.

Third parties

Message text and images are sent to Anthropic's API to extract event details, under Anthropic's API terms, which do not permit use of that data for model training. No data is sold, shared with advertisers, or disclosed to any other party.

Google API Services User Data Policy

The application's use of information received from Google APIs adheres to the Google API Services User Data Policy, including the Limited Use requirements. Calendar data is used only to provide the calendar-management function described here.

Access, deletion, and revocation

The family controls the account and can delete any event, the database, or the entire deployment at any time. Google access can be revoked at myaccount.google.com/permissions, which immediately stops the application from reading or writing calendars.

Contact

Questions about this policy: siefkencalendar@gmail.com