Pengu
Privacy Policy
This policy explains what data Pengu collects, why we collect it, who we share it with, and what
rights you have. It covers the website tiengtrungapp.com, the web app
nhamay.tiengtrungapp.com, and the Pengu mobile apps on the App Store and Google
Play (for example Pengu Tiếng Trung, app ID com.pengu.tiengtrungnhamay)
— together, the “Service”.
1. Who is responsible for your data
The Service is operated by the Pengu team (tiengtrungapp.com) in Vietnam. Pengu is the data controller for personal data you provide through the Service.
- Privacy contact: hotro@tiengtrungapp.com
- Contact page: tiengtrungapp.com/lien-he
2. What we collect and why
Our principle is collect as little as possible. The table below is the complete list of what the Service sends to Pengu servers.
| Data | When collected | Purpose | Legal basis |
|---|---|---|---|
| Account identifier: the email address or phone number you enter, and your password (stored only as a hash — Pengu cannot read your password) | Only when you choose to register or sign in (required for Premium and Invite-a-friend) | Create and authenticate your account, keep your Premium entitlement when you change devices | Performance of a contract |
| Device identifier (Android ID on Android; a random ID generated by the app and stored in the Keychain on iOS) | Each time you open the app | Count real users (DAU/MAU), prevent Invite-a-friend reward fraud | Legitimate interest |
| Environment info: platform (iOS/Android), app version, device language | Each app launch and when registering for notifications | Fix version-specific bugs, decide the minimum supported version | Legitimate interest |
| Install source (utm_source / utm_medium / utm_campaign, if you arrived from a campaign link) | First app launch | Understand which referral channels work | Legitimate interest |
| Lesson completion records: lesson ID, track ID, score percentage, device identifier | When you finish a lesson | See which lessons are too hard or get abandoned, and improve them | Legitimate interest |
| Synced learning progress: XP, streak, spaced-repetition schedule, completed lessons | Only while you are signed in — the primary copy stays on your device | Restore your progress after reinstalling or switching devices | Performance of a contract |
| Push notification token (Firebase Cloud Messaging) | Only if you allow notifications | Send study reminders and news; measure notification opens | Your consent |
| Purchase data: product ID, the purchase token issued by Apple/Google, timestamp, partner discount code if used | When you buy Premium | Verify the transaction with Apple/Google, unlock Premium, accounting and partner commission reconciliation | Contract + legal obligation (accounting) |
| Referral partner data: full name, phone number, bank details for commission payouts | Only if you sign up as a referral partner at /doi-tac/ | Pay commissions and reconcile accounts | Contract + legal obligation |
| Server logs: IP address, timestamp, requested path | Every request (automatic, as on any website) | Abuse prevention (rate limiting), security, debugging | Legitimate interest |
What we do NOT collect
- No contacts, messages, photos, calendar or GPS location.
- No real name or national ID from learners.
- No social login; we never pull data from your Facebook/Google/Zalo profile.
- We never sell, rent or trade your personal data.
3. Data that stays on your device
Most learning data is local — it stays in the app's storage on your phone (or in your browser's localStorage on the web) and never leaves your device unless you sign in and sync:
- XP, streaks, badges, spaced-repetition schedule, and your answers per lesson.
- Lesson content downloaded for offline study.
- The daily reminder time you set.
- A cached Premium status so the app works offline.
Uninstalling the app or tapping “Delete learning data” in Profile removes this from your device.
4. Microphone and pronunciation practice
The Speaking practice feature asks for microphone and speech recognition permission. Here is exactly how that data is handled:
- Recordings are written to the app's temporary folder on your device so you can play them back against the model audio. The app deletes these files when you leave the speaking screen.
- Pengu never uploads or stores your recordings.
- Speech-to-text is performed by your operating system's speech recognition service (Apple on iOS, Google on Android). Depending on your device and settings, those services may process audio on-device or on Apple/Google servers under their own privacy policies.
- You can decline microphone access — only pronunciation scoring is lost; everything else keeps working.
5. Advertising
Practice sessions can be unlocked by watching a short rewarded ad served by Google AdMob. This is what funds our servers and new lessons.
- Google may use your device's advertising identifier (Advertising ID / IDFA) and ad interaction data under the Google privacy policy.
- Pengu does not send Google your email address, phone number or learning content.
- On iOS, if you do not grant tracking permission via the App Tracking Transparency prompt, the ads you see are non-personalised.
- On Android you can turn off ad personalisation in Settings → Google → Ads, or reset/delete your advertising ID at any time.
- Buying Premium removes ads from the app entirely.
6. Analytics
The app uses Firebase Analytics (Google) to understand which screens are used and where learners drop off. The tiengtrungapp.com website uses a minimal page-view counter (page opened, browser type). These metrics are aggregated, used to improve the product, and are not used to identify you personally.
7. Sharing with third parties
We share data only with the service providers required to run the Service:
| Recipient | What they receive | Why |
|---|---|---|
| Cloudflare (server, database and media hosting) | All data listed in section 2, as stored and transmitted | Pengu's servers and database run on this platform |
| Google (AdMob, Firebase Analytics, Firebase Cloud Messaging, Google Play Billing) | Advertising identifier, app usage events, notification token, purchase token | Serve ads, measure usage, deliver notifications, process Android payments |
| Apple (App Store, StoreKit, Speech Recognition) | Purchase transaction data; audio when you use speech recognition on iOS | Process iOS payments and convert speech to text |
Beyond this, we disclose data only when required by a lawful request from a competent authority, or when necessary to protect the legal rights of Pengu and its users. We do not sell personal data.
8. Storage and international transfers
Pengu's infrastructure runs on Cloudflare's global network, and some providers listed in section 7 operate servers outside Vietnam. Your data may therefore be processed abroad. We only use providers with comparable data protection commitments, and all traffic is encrypted over HTTPS.
9. How long we keep data
- Account data: kept while the account exists. When you delete your account, sign-in is disabled immediately and the data described in section 10 is removed.
- Lesson completions and device pings: after account deletion these records are unlinked from you (the user field is cleared) and remain only as aggregate statistics.
- Purchase and transaction records: retained as required by Vietnamese accounting and tax law even after account deletion — but no longer tied to your identity.
- Server logs: kept briefly for abuse prevention and debugging.
10. Deleting your account and data
You can do this yourself, without contacting anyone:
- In the app: open the Profile tab → Delete account → confirm. This cannot be undone.
- By email: if you cannot open the app, send a request from the registered email address or phone number to hotro@tiengtrungapp.com; we process it within 30 days.
When an account is deleted:
- Your identifier (email/phone) and password are permanently invalidated — you can no longer sign in to any Pengu app, because one account is shared across the whole app suite.
- Premium entitlements, sessions, notification devices, invite codes and referrals are deleted. Any remaining Premium is lost and is not refunded.
- If you are a referral partner, your personal details (name, phone, bank account) are erased; only commission figures needed for reconciliation are retained.
- Learning data on your device remains until you uninstall the app or tap “Delete learning data”.
11. Your rights
Under Vietnam's Decree 13/2023/ND-CP on personal data protection (and the GDPR if you are in the EU/EEA) you may:
- Know what data we process about you and request a copy.
- Ask us to correct inaccurate data.
- Ask us to delete your data (see section 10).
- Withdraw consent at any time — for example by turning off notification or microphone permission in your device settings.
- Object to or restrict processing, and lodge a complaint with the competent supervisory authority.
Send requests to hotro@tiengtrungapp.com; we respond within 30 days. To protect you, we may need to verify that the request comes from the account holder.
12. Security
- All connections to Pengu servers use HTTPS.
- Passwords are stored only as hashes — not even the Pengu team can read your password.
- Sign-in tokens are stored in the operating system's secure storage (Keychain on iOS, Keystore on Android).
- One account is usable on one device at a time: signing in on a new device signs out the old one.
No system is perfectly secure. If a data breach affects you, we will notify you in the app and by email within the deadlines required by law.
13. Children
The Service is aimed at working adults and is not directed at children; it is not listed in any children's category on the app stores. We do not knowingly collect personal data from children under 13. People under 16 should use the Service only with the consent of a parent or guardian. If you believe your child has given us data, contact hotro@tiengtrungapp.com and we will delete it.
14. Changes to this policy
If we make significant changes we will update the date at the top of this page and notify you in the app before the changes take effect. Continuing to use the Service after the effective date means you accept the updated policy.
15. Contact
Privacy questions: hotro@tiengtrungapp.com or the contact page.
See also: Terms of Service · Chính sách bảo mật (tiếng Việt).