Privacy Policy
Last updated: June 14, 2026
1. Overview
Yumei ("we," "us," or "our") is committed to protecting your privacy. This Privacy Policy explains what information we collect, how we use it, who we share it with, and your rights regarding your data. By using the Yumei app ("the Service"), you agree to the practices described in this policy.
This policy applies to all users of the Yumei mobile application.
2. Information We Collect
2a. Information You Provide
- Account information — your name and email address when you register
- Profile preferences — your learning goals, current HSK level, and language settings
- User-generated content — custom decks, notes, and vocabulary lists you create within the app
2b. Voice and Audio Data
When you use AI Conversation or Precision Shadowing features, we collect:
- Voice recordings — audio captured during active practice sessions and processed by our locally run SenseVoice speech-to-text system for transcription
- Conversation transcripts — text transcripts of your AI practice sessions, stored to support session review and vocabulary tracking
Voice data is processed by Yumei-operated SenseVoice speech-to-text systems for transcription. Voice recordings and conversation transcripts are retained as described in Section 5 so you can review practice sessions and track learning progress.
2c. Learning and Usage Data
- Flashcard history — cards reviewed, ratings given, and FSRS scheduling data (stability, difficulty, retrievability scores)
- Session data — session start and end times, features used, and practice duration
- Vocabulary progress — words encountered, mastered, and currently under review
- HSK level tracking — your progress across HSK levels 1–7
2d. Device and Technical Data
- Device identifiers — device type, operating system version, and app version
- Crash and diagnostic data — error logs and performance data used to identify and fix bugs
- Usage analytics — anonymized data about how features are used to improve the app
2e. Payment Data
We do not collect or store your full payment card, bank account, or app store billing credentials. All purchases — including subscriptions and Extra Credits — are processed by your device's app store provider (Apple App Store or Google Play Store) and managed through RevenueCat. We receive purchase status, entitlement, product, transaction, and credit-balance information needed to provide paid features. Refer to your app store's and RevenueCat's privacy policies for information about how payment and purchase data is handled.
3. How We Use Your Information
We use the information we collect to:
- Provide the Service — deliver flashcard reviews, AI conversations, shadowing sessions, and dictionary search
- Personalize learning — adapt vocabulary difficulty, conversation complexity, and review schedules to your level
- Track progress — maintain your HSK dashboard, streak data, and learning insights
- Process purchases — verify subscription status and credit balances
- Improve the Service — analyze usage patterns to fix bugs and develop new features
- Communicate with you — send important service updates, account notifications, and support responses
- Comply with legal obligations — respond to lawful requests and enforce our Terms of Service
We do not use your data to serve third-party advertisements.
4. Third-Party Service Providers
To deliver the Service, we share certain data with the following third-party providers. Each is contractually obligated to process your data only as directed by us and in compliance with applicable privacy laws.
| Provider | Purpose | Data Shared |
|---|---|---|
| Amazon Web Services (AWS) | AI conversation generation, cloud audio storage, and supporting infrastructure | Conversation context, transcripts, voice audio, generated responses, and storage metadata |
| Azure Cognitive Services | Text-to-speech audio generation | Text prompts for AI voice responses |
| OpenAI | Semantic search embeddings | Dictionary search queries |
| PlanetScale | Cloud database hosting | All stored user data |
| RevenueCat | Subscription and in-app purchase management | App user ID, purchase status, entitlement, product, transaction, and store information |
| PostHog | Product analytics, masked session replay, diagnostics, and error reporting | App usage events, device and technical data, diagnostics, and error reports |
We do not sell your personal information to any third party.
5. Data Retention
| Data Type | Retention Period |
|---|---|
| Account information | Until account deletion |
| Learning and flashcard data | Until account deletion |
| Conversation transcripts | Until account deletion |
| Voice audio | Until account deletion |
| Crash and diagnostic logs | 30 days |
| Anonymized analytics | Indefinitely |
You may request deletion of your data at any time as described in Section 8.
6. Children's Privacy
The Service is not directed to children under the age of 13. We do not knowingly collect personal information from children under 13. If we become aware that we have inadvertently collected information from a child under 13, we will delete it promptly. If you believe a child under 13 has provided us with personal information, please contact us at support@yumei.ai.
Users between 13 and 17 may use the Service only with parental or guardian consent.
7. Your Privacy Rights
California Residents (CCPA)
If you are a California resident, you have the right to:
- Know what personal information we collect, use, disclose, and sell
- Delete your personal information, subject to certain exceptions
- Opt out of the sale of your personal information (we do not sell personal information)
- Non-discrimination — we will not discriminate against you for exercising your rights
To exercise these rights, contact us at support@yumei.ai.
European Economic Area, UK, and Switzerland (GDPR)
If you are located in the EEA, UK, or Switzerland, you have the right to:
- Access the personal data we hold about you
- Rectify inaccurate or incomplete personal data
- Erase your personal data ("right to be forgotten")
- Restrict processing of your personal data
- Data portability — receive your data in a structured, machine-readable format
- Object to processing based on legitimate interests
- Withdraw consent at any time where processing is based on consent
Our legal basis for processing your data is:
- Contract performance — to provide the Service you signed up for
- Legitimate interests — to improve and secure the Service
- Consent — for voice data processing and optional features
To exercise your rights or lodge a complaint, contact us at support@yumei.ai. You also have the right to lodge a complaint with your local data protection authority.
8. Account Deletion and Data Requests
You may delete your account at any time through the App settings under Profile → Delete Account. Upon deletion:
- Your account and profile data will be permanently deleted within 30 days
- Conversation transcripts and voice audio associated with your account will be deleted within 30 days
- Anonymized, aggregated analytics data that cannot be linked to you may be retained
- Data required for legal compliance may be retained for the minimum required period
To submit a data access, correction, or deletion request directly, email support@yumei.ai with the subject line "Privacy Request."
9. Data Security
We implement industry-standard technical and organizational measures to protect your personal information, including:
- Encryption of data in transit (TLS) and at rest
- Access controls limiting data access to authorized personnel
- Regular security assessments and monitoring
No method of transmission over the internet is 100% secure. While we strive to protect your data, we cannot guarantee absolute security. In the event of a data breach affecting your rights, we will notify you as required by applicable law.
10. Data Transfers
Yumei is operated from the United States. If you are located outside the United States, your data will be transferred to and processed in the United States and other countries where our service providers operate. We ensure appropriate safeguards are in place for such transfers in compliance with applicable law, including Standard Contractual Clauses for transfers from the EEA.
11. Academic Research
Yumei is piloted in partnership with Purdue University. Participation in any research study associated with this partnership is voluntary, governed by a separate informed consent process, and subject to institutional review board (IRB) oversight. Research participation does not affect your access to the Service. Anonymized, aggregated learning outcome data may be used for academic research purposes only with appropriate ethical oversight.
12. Changes to This Policy
We may update this Privacy Policy from time to time. We will notify you of material changes through the App or by email prior to the changes taking effect. Your continued use of the Service after the effective date constitutes acceptance of the updated policy. We encourage you to review this policy periodically.
13. Contact
For privacy-related questions, requests, or concerns:
Email: support@yumei.ai Subject line for data requests: "Privacy Request"
For app store subscription management: your device's app store account settings For payment refunds: your device's app store support page