This English page is provided for convenience (for example, for App Store review). The Vietnamese version at privacy.html is the primary, authoritative version of this policy.
Ai Lịch ("we") respects your privacy. This policy explains what information Ai Lịch collects, how we use, share, and protect it when you use the Ai Lịch website and iOS app.
1. Core principle: fully usable without an account
Ai Lịch's calendar features work 100% without signing in. In that mode, your events and profile (birth year, display preferences...) are stored only on your own device and are never sent to our servers.
All lunar/solar date conversion, Can Chi (heavenly stems and earthly branches), solar terms, and auspicious-hour calculations run entirely on-device (offline) — no data is transmitted to perform these calculations.
2. Information collected when you sign in
Signing in is optional and used to back up and sync your data across devices. If you choose to sign in with Sign in with Apple or Google, we receive an account identifier (uid) and whatever information you authorize that provider to share (e.g. name, email).
Once signed in, the following data is synced to Firebase (Google Cloud) to enable multi-device sync:
- Profile: birth year, gender (optional, may be left blank), display preferences.
- Calendar events: title, date (lunar or solar), recurrence rule, notes, reminder offsets.
- Subscription status: free or Pro tier, and its validity period.
3. Natural-language event input
In the current version, the sentence you type to create an event (e.g. "grandfather's death anniversary, 20th day of the 7th lunar month, every year") is parsed entirely on-device, never leaves your device, and is not sent to any third party. If we later add a server-side processing layer for more complex phrasing, this policy will be updated to state exactly what minimal data would be sent and why.
4. App analytics and crash reporting
We use Firebase Analytics and Firebase Crashlytics to understand how the app is used and to catch bugs. This data consists of usage metrics and technical crash logs, and is not intended to identify you personally.
5. Who we share data with
We do not sell your personal information. Data is processed by the following infrastructure providers, acting as data processors:
- Firebase (Google): authentication, sync storage (Firestore), analytics, crash reporting.
- Apple: processes Sign in with Apple and in-app purchases via the App Store.
6. Data retention and deletion
When you delete an event, it is removed immediately from your device and from the sync server (if you are signed in) — there is no temporary retention period.
You can delete your account directly in the app (More › Account). Deleting your account removes your synced server-side data immediately; data stored locally on a device remains under your control on that device.
7. Your rights
You have the right to access, correct, or request deletion of your personal data. Please send requests to nextapps2024@gmail.com.
8. Children
Ai Lịch is not directed at children under 13, and we do not knowingly collect data from children in that age group.
9. Changes to this policy
We may update this policy as the service evolves, particularly if advertising, device attestation, or server-side AI features are added in future versions. The updated version will be posted on this page along with its update date.
10. Contact
For privacy questions, contact: nextapps2024@gmail.com.