Last updated: April 5, 2026

Privacy Policy

Mingdao ("we", "us", "our") is a Chinese language learning platform built by Frederico Luz. This policy explains what data we collect, how we use it, and your rights.

What We Collect

Account information: Your email address and password, used to create and secure your account.

Learning data: Flashcard progress, vocabulary scores, reading history, conversation messages, pronunciation assessment results, study streaks, and daily goal settings. This data powers your personalized learning experience.

Analytics: We use PostHog (EU-hosted) to track how you interact with the app — pages visited, features used, session timing, and device/platform information. This data is linked to your account to help us understand and improve your learning experience.

Push notification tokens: If you enable notifications, we store a device token to send you study reminders. You can disable notifications at any time.

How We Use Your Data

  • To provide personalized learning (spaced repetition, adaptive reading difficulty, conversation scenarios)
  • To track your progress across sessions and devices
  • To improve the app based on usage patterns
  • To send study reminders (if enabled)

We do not use your data for advertising or sell it to third parties.

AI & Third-Party Services

Mingdao uses AI to power conversations and reading generation. When you use these features:

  • Conversation messages are sent to AI language model providers (via OpenRouter) to generate tutor responses. These providers process your messages to respond but do not use them for model training.
  • Pronunciation audio is sent to Microsoft Azure (EU) for speech-to-text transcription, and to iFlytek for pronunciation assessment scoring. Only the audio clip and reference text are transmitted.
  • Reading generation uses AI models to create personalized passages based on your vocabulary level.

Your conversation content is stored on our servers (Supabase, EU-hosted) for learning continuity — so the tutor remembers context within a session.

Third-Party Services

Service Purpose Data Shared Location
Supabase Database & authentication Account, learning data EU
OpenRouter AI conversation & reading Messages, vocabulary level US (processing only)
Microsoft Azure Speech-to-text transcription Audio clips EU
iFlytek Pronunciation scoring Audio clips, reference text China
PostHog Analytics Usage events, device info EU

Data Storage & Retention

All primary data is stored in Supabase servers in the European Union. Your data is retained for the duration of your account. You can request deletion at any time (see Your Rights below).

Your Rights (GDPR)

You have the right to:

  • Access your data — request a full export of your learning data
  • Correct inaccurate data
  • Delete your account and all associated data
  • Object to analytics processing
  • Withdraw consent for push notifications at any time

To exercise any of these rights, email us at [email protected]. We will respond within 30 days.

Security

We use industry-standard security measures including encrypted connections (HTTPS), secure authentication (Supabase Auth), and server-side API key management. No AI provider credentials are ever exposed to your browser.

Age Requirement

Mingdao is intended for users aged 16 and older. If you are under 16, you need parental or guardian consent to use the app.

Pilot Program

Mingdao is currently in a pilot phase with the Confucius Institute of Lisbon. During the pilot, the service is provided free of charge. Features, limits, and availability may change as we develop the platform.

Changes to This Policy

We may update this policy as the app evolves. Significant changes will be communicated via the app or email.

Contact

Frederico Luz
[email protected]