Zhong Sign in

Privacy Policy

Last Updated: December 2025

Zhong ("we", "our", or "the App") is an independent language learning tool developed and operated in Taipei, Taiwan. We believe your learning data belongs to you. We do not sell your personal data to advertisers or third parties.

1. Data We Collect

To provide our services, we collect and store the following information:

  • Account Information: We use Clerk for authentication. We store your email address and a unique User ID to identify your account.
  • Learning Data: We store your vocabulary progress, review history (timestamps, grades), and course settings. This data is essential for our Spaced Repetition (FSRS) algorithm to calculate your optimal review schedule.
  • Payment Data: We use Stripe to process payments. We do not store your credit card information on our servers. We only store a reference to your subscription status and transaction history to verify your license.
  • Technical Logs: For security and debugging, our servers (hosted on dedicated infrastructure) temporarily log IP addresses and browser user-agent strings.

2. How We Use Your Data

We use your data solely for the following purposes:

  • To calculate when you should review specific vocabulary words.
  • To sync your progress across devices.
  • To grant access to premium features based on your license status.
  • To prevent abuse and ensure the security of our platform.

3. Third-Party Service Providers

We share data only with the infrastructure providers necessary to run the App:

  • Clerk: For secure user authentication and identity management.
  • Stripe: For payment processing and license validation.
  • Cloudflare R2: For secure database backups and asset delivery.

4. Data Retention

We retain your learning history for as long as your account is active. This ensures that even if your license expires and you return later, your learning progress remains intact.

5. Your Rights

You have the right to:

  • Access: Request a copy of the data we hold about you.
  • Deletion: Request the permanent deletion of your account and all associated learning data.

6. Contact Us

If you have questions about this policy or wish to exercise your rights, please contact us at: [email protected].