Privacy Policy
Effective 10 July 2026
- No accounts, no sign-up — the app works without knowing who you are.
- No ads, no ad networks, no ad identifiers, ever.
- No personal information is collected from you or your child.
- Your child's progress (stars, stickers) is stored only on your device.
- We receive only anonymous usage statistics and crash reports, used solely to improve the app.
Who we are
Voivoi ("we", "us") is a bilingual early-learning app for children aged 2–6, developed by Khoa Nguyen, an independent developer based in Vietnam. Questions about this policy: nguyendangkhoa96nt@gmail.com.
What we do NOT collect
- No names, email addresses, phone numbers, photos, contacts, or location.
- No account registration of any kind.
- No advertising identifiers (IDFA / Android advertising ID) — collection is disabled in the app's configuration, and the app contains no advertising or marketing SDKs.
- No messages, recordings, or content created by your child — the app has no chat, no camera, no microphone use.
What we collect (anonymous)
Usage statistics. The app sends a small, fixed set of anonymous events (for example: lesson started, lesson completed, answer correct on first try, voice language toggled) via Google Firebase Analytics. These are tied to a random app-instance identifier, not to any person. Ad personalization signals are turned off. We use these numbers only to understand which lessons work and to improve the app.
Crash reports. If the app crashes, Firebase Crashlytics sends a technical report (device model, operating system version, and what the code was doing) so we can fix the bug. Crash reports contain no personal information.
On your device only. Your child's learning progress — stars, stickers, streaks, per-word accuracy — and settings are stored locally on your device. They never leave it, and deleting the app deletes them.
Children's privacy
Voivoi is designed for children and built to comply with the Children's Online Privacy Protection Act (COPPA), the GDPR's rules for children, and the Apple Kids Category / Google Play Families requirements. We do not knowingly collect personal information from anyone, including children. Grown-up areas of the app (settings, any purchase or external link) sit behind a parental gate.
Service providers
Anonymous statistics and crash reports are processed by Google LLC (Firebase Analytics and Firebase Crashlytics) on our behalf, configured with ad personalization disabled. See Firebase Privacy and Security. We do not sell data. We do not share data with anyone for advertising or marketing.
Purchases
If the app offers purchases (for example, unlocking all lesson packs), payment is handled entirely by Apple's App Store or Google Play. We never see your payment details. Purchases in Voivoi are protected by a parental gate.
Data retention and deletion
- Local progress and settings: on your device until you delete the app.
- Anonymous analytics: retained by Firebase for up to 14 months, then deleted automatically.
- You can ask us to delete the analytics data linked to your app instance — email us and we will action it via Firebase's deletion tools.
Changes to this policy
If we change this policy, the new version will be posted at this address with a new effective date. Material changes will be noted in the app's grown-ups area.
Contact
Khoa Nguyen — nguyendangkhoa96nt@gmail.com