Privacy Policy
Hanyu — Learn Mandarin Chinese
Last updated: March 20, 2026
Overview
Hanyu (“we”, “our”, or “the app”) is a Mandarin Chinese learning application designed for English speakers. We are committed to protecting your privacy. This policy explains what information we collect, how we use it, and your rights.
When you register, we collect:
- Your name
- Your email address
- A hashed (encrypted) password — we never store your password in plain text
Learning Progress
Your learning progress (mastered initials, finals, characters, quiz scores, study streaks) is stored locally on your device using iOS UserDefaults. This data is not transmitted to our servers.
- We do not collect location data
- We do not collect device identifiers or advertising IDs
- We do not track your behavior across other apps or websites
- We do not sell your data to third parties
- We do not use third-party analytics or advertising SDKs
We use your account information solely to:
- Authenticate your identity when you sign in
- Associate your account with your locally stored learning progress
- Provide customer support if you contact us
Data Storage and Security
- Account data (name, email, hashed password) is stored on our secure backend hosted on Cloudflare Workers with D1 database
- Passwords are hashed using PBKDF2 with SHA-256 — your actual password is never stored
- Learning progress data is stored entirely on your device and never leaves it
- We use HTTPS for all network communication
Data Retention
- You may delete your account at any time by contacting us at the email below
- Upon account deletion, we will permanently remove your account data from our servers within 30 days
- Locally stored learning progress can be cleared by uninstalling the app
Children’s Privacy
Hanyu is designed for general audiences and does not knowingly collect personal information from children under 13. If you believe a child under 13 has provided us with personal information, please contact us and we will delete it promptly.
Changes to This Policy
We may update this Privacy Policy from time to time. We will notify users of significant changes by updating the “Last updated” date at the top of this page.
If you have any questions about this Privacy Policy, please contact us at:
Email: chengchenglonglong@gmail.com
This privacy policy applies to the Hanyu iOS application.