Privacy Policy
Privacy Policy
Last updated: July 18, 2026

1. Who we are

SlashHanzi is a Chinese-learning app operated by Cumulus Labs Limited, a company registered in Hong Kong ("we", "us"). This policy explains what information we collect when you use the app, how we use it, and the choices you have.

If you have any question about this policy or your data, contact us at [email protected].

2. Information we collect

Account information. When you register we collect your email address, the display name you choose, and your password. Passwords are stored only in salted, hashed form — we cannot read them. Email verification codes are generated and stored temporarily to confirm your address.

Sign-in with Apple or Google (where available). If you use a social sign-in, the provider shares your account identifier, and — depending on your choices — your name and email address. We do not receive your password for those services.

Learning activity. Your study progress, quiz and drill results, streaks, session statistics, chosen decks, and app settings, so your learning can continue across sessions and devices.

Conversation content. Messages you type or speak to the AI conversation partner, and the AI replies, are stored with your account so you can review past sessions.

Voice recordings. When you use speech input, the audio you record is processed to transcribe it into text. When the app speaks, the text is processed to synthesize audio.

Feedback. Anything you submit through the in-app feedback form.

Technical data. App version, platform, and standard server request logs (IP address, timestamps) kept for security and operations.

We do not use third-party advertising or analytics SDKs in the app.

3. AI providers

The core of the app is conversation with an AI partner. To provide it, some of your data is sent to third-party AI service providers:

  • Your conversation messages are sent to large-language-model providers (for example Moonshot AI, OpenAI, or others depending on service configuration) to generate the AI replies and suggestions.
  • Your voice recordings are sent to speech-recognition providers to transcribe them.
  • Text is sent to text-to-speech providers (for example MiniMax) to synthesize spoken audio.

This data is sent solely to provide the feature you are using. Please avoid including sensitive personal information (such as financial details, government IDs, or health information) in your conversations — the AI partner does not need it, and we do not want to receive it.

4. How we use your information

  • To provide, maintain, and improve the service — including saving your progress and generating AI conversations, transcriptions, and audio.
  • To secure your account and our infrastructure, and to prevent abuse.
  • To send service emails, such as verification codes.
  • To respond to feedback and support requests.

We do not sell your personal information, and we do not share it with third parties for their own advertising.

5. Where your data is stored

Our servers run on cloud infrastructure providers (currently Amazon Web Services). Service email is delivered via Cloudflare. AI providers process data on their own infrastructure as described in section 3. Your data may therefore be processed in jurisdictions different from where you live.

6. Data retention and deletion

We keep your data for as long as your account is active. To delete your account and its associated data, email [email protected] from your registered address — we will complete the deletion within 30 days. Limited records (such as server logs) may be retained for a short period afterwards for security and legal purposes.

7. Your rights

You may request access to, correction of, or deletion of your personal data at any time by contacting [email protected]. Where local law grants you additional rights (such as data portability or the right to object to processing), we will honor them.

8. Children

The app is not directed at children under 13, and we do not knowingly collect personal information from them. If you believe a child has created an account, contact us and we will delete it.

9. Security

Data is encrypted in transit (TLS), passwords are stored hashed, and access to production systems is restricted. No method of transmission or storage is completely secure, but we work to protect your information appropriately.

10. Changes to this policy

We may update this policy as the app evolves. We will update the date above, and for material changes we will notify you in the app before they take effect.

11. Contact

Cumulus Labs Limited, Hong Kong — [email protected].

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