Privacy Policy

Last updated: January 2026

Summary

Terasu is designed with privacy in mind. Your data stays on your device by default. We only collect data when you explicitly choose to sync or sign in.

Data We Collect

Local Data (Default)

When you use Terasu without signing in:

All your items, comparisons, and rankings are stored locally in your browser
This data never leaves your device
We have no access to this data

Cloud Sync (Optional)

When you sign in with Google:

Your email address (for account identification)
Your items and comparisons (encrypted in transit)
Sync metadata (timestamps)

This data is stored in Firebase (Google Cloud) and is used solely to sync your data across your devices.

Analytics (Optional)

We use Firebase Analytics to understand how people use Terasu:

Page views
Feature usage (anonymous)
Error reports

This data is anonymous and does not include your personal information or the content of your items.

Data Sharing

We do not sell, rent, or share your personal data with third parties. Your data is only used to provide the Terasu service.

Data Security

All data in transit is encrypted using HTTPS/TLS
Cloud data is stored securely in Firebase (Google Cloud)
Only you can access your cloud data (authenticated by your Google account)

Data Deletion

You can delete your data at any time:

Local data: Clear your browser's local storage or use the "Clear All" button in the app
Cloud data: Delete your account from the Settings page

Cookies

Terasu uses essential cookies for:

Authentication (keeping you signed in)
Local preferences (theme, settings)

We do not use tracking cookies for advertising.

Children's Privacy

Terasu is not intended for children under 13. We do not knowingly collect data from children.

Changes to This Policy

We may update this policy from time to time. Changes will be posted on this page with an updated date.

Contact

Questions? Open an issue on GitHub.