Privacy Policy for Lịch Âm

Effective date: May 2026

Lịch Âm is a Vietnamese lunar calendar reminder app developed by DNK Software.

This Privacy Policy explains how we collect, use, store, and protect your information when you use the Lịch Âm mobile application.

By using Lịch Âm, you agree to the practices described in this Privacy Policy.

1. Information We Collect

Lịch Âm may collect and store the following information:

  • Google account email address, if you choose to sign in with Google
  • User ID created by our authentication provider
  • Lunar calendar events you create, such as event title, lunar date, reminder settings, and notes
  • Sync metadata such as created time, updated time, and sync status
  • Google Calendar event ID, if you choose to sync events to Google Calendar

You may use the app offline without signing in. In offline mode, your event data is stored only on your device.

2. How We Use Your Information

We use your information to:

  • Save your lunar calendar reminders
  • Show upcoming lunar events
  • Schedule local reminder notifications
  • Sync your data across devices when you sign in
  • Restore your data after reinstalling the app
  • Create or update Google Calendar events when you manually choose to sync

We do not use your personal data for advertising or selling to third parties.

3. Offline Use

Lịch Âm can be used without creating an account.

If you use the app offline:

  • Your events are stored locally on your device
  • Your data is not synced to the cloud
  • If you uninstall the app before signing in and syncing, your local data may be deleted from your device

4. Google Sign-In

Lịch Âm uses Google Sign-In only to identify your account and support optional cloud sync.

When you sign in with Google, we may access:

  • Your Google account email address
  • Basic profile information required for authentication

We do not access your Google password.

Your Google account is used to create or identify your user account in our authentication system.

5. Cloud Sync

If you sign in with Google, your event data may be securely synced to our cloud database through Supabase.

Cloud sync is used to:

  • Back up your lunar events
  • Restore your events after reinstalling the app
  • Sync events across your devices

You may continue using the app without cloud sync if you do not sign in.

6. Google Calendar Sync

If Google Calendar sync is available and you choose to use it, Lịch Âm may request permission to create or update events in your Google Calendar.

Google Calendar sync is optional and manual.

The app does not automatically sync events to Google Calendar without your action.

When syncing to Google Calendar:

  • The app creates or updates calendar events for your selected lunar events
  • The app does not create yearly recurring Google Calendar events
  • The app does not add Google Calendar reminders by default
  • Lịch Âm local notifications remain the main reminder system

We are not responsible for changes, deletion, or behavior of events inside Google Calendar after they are synced.

7. Local Notifications

Lịch Âm uses local notifications to remind you of events.

Reminder notifications are scheduled on your device.

We do not use server push notifications for lunar reminders.

Notification delivery may depend on:

  • Your device settings
  • Notification permissions
  • Operating system behavior
  • Battery optimization settings
  • Time zone settings

We try to provide timely reminders, but we cannot guarantee that notifications will always be delivered exactly on time.

8. Data Sharing

We do not sell your personal data.

We do not share your personal data with advertisers.

We use trusted service providers only to operate the app, including:

  • Google Sign-In for authentication
  • Google Calendar API for optional calendar sync
  • Supabase for cloud authentication and database sync

These service providers process data only as needed to provide app functionality.

9. Data Security

We use HTTPS and standard security practices to transmit data securely.

Access to synced data is protected by user authentication and database access rules.

However, no method of transmission or electronic storage is completely secure. We cannot guarantee absolute security.

10. Data Retention

Offline data remains on your device until you delete it or uninstall the app.

Cloud data may remain stored until:

  • You delete events inside the app
  • You request deletion of your account-related cloud data
  • We remove data according to our operational or legal requirements

Deleted events may be marked for deletion in cloud sync before being removed or hidden from active use.

11. Data Deletion

You may delete events directly inside the app.

If you want to request deletion of your account-related cloud data, please contact us at:

Email: contact@dnksoft.vn

We may need to verify your request before deleting cloud data.

12. Children’s Privacy

Lịch Âm is not designed for children under 13.

We do not knowingly collect personal data from children under 13.

If you believe a child has provided personal data through the app, please contact us so we can delete it.

13. Third-Party Services

Lịch Âm may use third-party services, including:

  • Google
  • Supabase

These services may collect and process data according to their own privacy policies and terms.

You should review the privacy policies of these services if you use related features.

14. Changes to This Privacy Policy

We may update this Privacy Policy from time to time.

If we make changes, we will update the effective date at the top of this page.

Your continued use of the app after changes means you accept the updated Privacy Policy.

15. Contact Us

If you have questions about this Privacy Policy or want to request data deletion, please contact us:

DNK Software
Email: contact@dnksoft.vn
Website: https://dnksoft.vn