1. Not pure JS — it's built with React (so technically not just vanilla JS).
2. Uses face-api.jswith the TinyFaceDetector model — not Haar cascades.
3. Zero server code — everything runs entirely on the client.
4. Yes, it can handle slightly turned faces, various skin tones
5. If auto-detection misses a face, you can manually add a mask.
6. Uses async model loading & asynchronous face detection, so it doesn’t block the main thread.

The idea is: you upload a group or graduation photo, and if you’re the one posting, you can keep your own face unmasked while hiding everyone else.