Air Qin · Privacy Policy

Air Qin (無絃琴) is a virtual guqin — a Chinese seven-string zither — played in the air using your device’s camera. Our privacy position fits in one sentence: your camera imagery and your data stay on your device; we do not collect, upload, or sell any personal information. The details follow.

1. Camera imagery: processed entirely on your device

Hand tracking is performed on your device by an on-device model (MediaPipe HandLandmarker). The camera feed is used only for real-time inference and on-screen display; it is never uploaded, stored, or transmitted to any server. Processing stops the moment you close the app. The app contains no code path that sends imagery off the device.

2. What is stored locally

The following is saved only in local storage on your device, solely to make the app work, and is never uploaded:

• Practice progress and achievements: stars per piece, best accuracy, play counts, onboarding completion;
• Daily-phrase check-in date and streak;
• Preferences: mirroring, hui snapping, blind-score mode and other toggles;
• Your seal text (the “Zhiyin” feature), entered by you and used only to draw the watermark locally;
• Entitlement flag (whether you are a Zhiyin) and anonymous usage counters (launches, plucks, recordings), used for diagnostics only when you choose to share a “report”.

Clearing the app’s data or deleting the app permanently removes all of the above. We cannot access it and cannot restore it.

3. Recording and sharing: initiated by you, owned by you

Performance videos are generated on your device only when you start a recording, and are saved to your device. Sharing happens through the system share sheet at your initiative. The seal watermark and closing frame are part of the picture and carry no tracking capability. The diagnostic text produced by the “report” feature works the same way: what you see is what it contains, and it leaves your device only when you choose to share it.

4. No accounts, no identity data

The app has no registration and no sign-in. It does not collect your name, phone number, email address, contacts, location, or any other identity or sensitive personal information. There is no user profiling and no personalized advertising.

5. Purchases and entitlements

In-app purchases (such as the one-time “Zhiyin” unlock) are handled by the Apple App Store. Payment information is managed by Apple under its own privacy policy; we never see or store any payment data. Your entitlement is verified and restored on-device from Apple’s transaction receipt and is tied to your Apple ID — no separate account is needed.

6. Third-party services

The web version is hosted on GitHub Pages, whose server access logs (such as IP addresses) are handled by GitHub under its privacy policy. The app embeds no advertising SDKs, no analytics SDKs, no third-party trackers, and no cloud AI services. The hand-tracking model ships with the app and runs locally.

7. Children

The app is intended for a general audience and does not knowingly collect information from children — as stated above, we do not collect personal information from anyone. We recommend that minors use the app with a guardian present, and that everyone stay aware of their surroundings while playing with raised arms.

8. Changes and contact

If this policy changes materially, we will update the date on this page and notify you inside the app. For any privacy question, contact liujunshuo1987@gmail.com.

See also the Air Qin Terms of Use.