Privacy Policy

Last updated: May 15, 2026

Chifanlema ("we", "our", or "the app") is a Mandarin Chinese vocabulary learning app. This policy explains what data we collect, why, and how we protect it.

1. Data We Collect

We collect the following data when you use Chifanlema:

• Email address — used to create and manage your account.
• User ID — a unique identifier assigned to your account by our authentication system.
• Learning activity — which vocabulary words you have seen, your selected HSK level, and daily word goal. This is used to personalize your word feed and avoid showing repeated words.
• Search queries — when you use the in-app dictionary search, your query is sent to our server to return results. If the query requires AI assistance, it is processed by a third-party AI language model provider to generate explanations and word breakdowns. Search queries are processed in real time and are not stored by the AI provider.
• Text-to-speech input — when you use the AI pronunciation feature, the Chinese text is sent to a third-party text-to-speech provider (SiliconFlow) to generate audio. The text is processed in real time; generated audio is cached on our servers to reduce repeated API calls but is not shared further.
• Ad identifiers — if you use the free (ad-supported) version, Google AdMob may collect your device advertising ID to serve personalized ads. You can opt out of personalized ads in your device settings.

2. How We Use Your Data

• Account management — to let you sign in, manage your profile, and sync progress across devices.
• App functionality — to deliver personalized vocabulary based on your level and learning history.
• Search — to process dictionary search requests in real time.

3. Data Sharing

We do not sell or transfer your personal data to any third party for their own marketing purposes. Your data stays on our servers (hosted on Supabase, with infrastructure on AWS in the Asia Pacific region).

We use the following third-party services that may process data on our behalf:

• Google AdMob — serves ads in the free version. May collect device identifiers and usage data for ad personalization. See Google's Privacy Policy.
• RevenueCat — manages premium subscriptions. Processes purchase receipts and subscription status. See RevenueCat's Privacy Policy.
• AI Language Model Provider — processes search queries to generate explanations when the local dictionary cannot answer your question. Queries are sent in real time and not stored by the provider.
• SiliconFlow — generates AI text-to-speech audio for Chinese pronunciation. Only the Chinese text you request is sent; no personal identifiers are included in the request.

When you sign in with Google or Apple, those providers may collect data according to their own privacy policies. We only receive your email address and basic profile information from them.

4. Data Storage and Security

All data is transmitted over HTTPS/TLS encryption. Your data is stored in a PostgreSQL database hosted on Supabase with row-level security policies. Passwords are never stored in plain text — authentication is handled by Supabase Auth using industry-standard hashing.

5. Data Retention

We retain your data for as long as your account is active. If you delete your account, all associated data (profile, learning history, seen words) is permanently deleted within 48 hours.

6. Your Rights

You can:

• Delete your account and all associated data at any time via the Settings screen in the app or through our account deletion page.
• Request your data by contacting us at the email below.

7. Children's Privacy

Chifanlema is not directed at children under 13. We do not knowingly collect data from children under 13. If you believe a child has provided us with personal data, please contact us and we will delete it.

8. Changes to This Policy

We may update this policy from time to time. Changes will be posted on this page with an updated date. Continued use of the app after changes constitutes acceptance of the updated policy.

9. Contact

If you have questions about this privacy policy or your data, contact us at:

hungcq.chifanlema@gmail.com