How face search works, and what happens to your face data

When a guest uploads a selfie, Facely finds every event photo with the same face in it, out of thousands, in about two seconds. Here's what actually happens, what it's good and bad at, and what is kept.

1. Finding the faces in each photo

When an event is created, every photo in the photographer's Drive folder is scanned once. A face detector finds each face in each photo, whether it's a portrait or a group shot with dozens of people.

2. Turning each face into a "fingerprint"

Each face is turned into a list of 512 numbers by a face-recognition model. The model is trained so that two photos of the same person produce similar lists, and photos of different people produce very different ones. That list is the face index: it's numbers, not a picture.

3. Matching a selfie

The guest's selfie goes through the same two steps, and its fingerprint is compared with every face in that event. Only faces that are a strong match count. The threshold is set well above the similarity two different people usually reach, so it errs towards not showing a stranger's photo. Each matching photo appears once, even if the guest is in it twice.

How accurate is it?

In our tests, a person's own photos score far above anyone else's when the face is clear, which keeps the matching dependable. It can miss photos where:

• the face is very small, for example the back rows of a huge group or wide stage shots;
• the face is in strong profile, turned away, or largely covered (veils, sunglasses, masks, hands);
• the selfie itself is dark, blurry or at an extreme angle.

The fix is almost always a better selfie: front-facing, good light, nothing covering the face. Very close family members can look alike to any face-recognition system, so a sibling's photo can occasionally appear. Guests simply ignore it.

What is stored, and for how long

• Guest selfies: used once for that search and deleted immediately. Never stored, reused or used for training.
• The photographer's photos: never copied off their Google Drive. Facely keeps small preview thumbnails so results load quickly.
• The face index (the number lists) and thumbnails: kept for 60 days so guests can search, then deleted automatically. Deletion on request within 48 hours.
• Search results: a guest's result page is a private link, kept for 7 days.

Everything is served over HTTPS. Nothing is sold or shared with third parties. The full details are in the privacy policy.

Who can search an event?

Anyone with the event's QR code or guest link, the people the photographer shares it with. Search results show only photos matching the uploaded face, never the whole album.