Privacy Policy

Last updated: February 9, 2026

I Ching Diary is a personal journal application for recording and reflecting on I Ching readings. This policy explains what data is collected, how it is used, and how it is stored.

1. Information We Collect

When you sign in with Google, we receive the following from your Google account:

Your name and email address
Your Google account profile photo
A unique account identifier

When you use the application, we store the data you provide:

Questions you ask the I Ching
Hexagram casting results and changing lines
Personal notes you write about your readings
AI-generated interpretations (delineations) of your readings
Dates and timestamps of your readings

2. How Your Data Is Used

Your data is used solely to provide the I Ching Diary service to you. Specifically:

Your Google account information is used to authenticate you and restrict access to your own readings.
Your reading data is stored so you can revisit and reflect on past consultations.
Your questions and hexagram results may be sent to OpenAI's API to generate interpretive delineations. This happens only when you request an interpretation.

Your data is never sold, shared with advertisers, or used for marketing purposes.

3. Third-Party Services

I Ching Diary relies on the following third-party services:

Google Firebase — authentication, data storage (Cloud Firestore), and hosting. Google's privacy policy applies to their infrastructure services.
OpenAI — reading data sent for AI-generated interpretations is subject to OpenAI's privacy policy. Data is sent via server-side Cloud Functions and is not sent directly from your browser.
Google Fonts — font files are loaded from Google's servers, which may log standard web request data (IP address, browser type).

4. Data Storage and Security

All reading data is stored in Google Cloud Firestore. Access is restricted by Firebase Security Rules so that only you can read and modify your own data. Authentication is handled by Firebase Authentication using your Google account.

Data is transmitted over HTTPS and encrypted in transit. Firestore data is encrypted at rest by Google Cloud.

5. Data Retention and Deletion

Your data is retained as long as your account exists. You can delete individual readings at any time from within the application. If you wish to delete all your data and your account, please contact us and we will remove your data from our systems.

6. Cookies and Tracking

I Ching Diary does not use cookies for advertising or tracking. Firebase Authentication uses browser storage (local storage and session cookies) solely to maintain your login session. No analytics or tracking scripts are used.

7. Children's Privacy

I Ching Diary is not directed at children under 13. We do not knowingly collect personal information from children under 13.

8. Changes to This Policy

We may update this privacy policy from time to time. Changes will be reflected by updating the "Last updated" date at the top of this page.

9. Contact

If you have questions about this privacy policy or your data, please open an issue on the project's repository or contact the developer directly.