Café table · nothing armed

Your laptop, left on the table

Yowl sits in the menu bar. No window, no Dock icon. Nothing is watching until you press Arm — the camera is not running and nothing is being recorded.

Yowl disarmed, showing an Arm button — the actual app, photographed

Yowl armed, saying to unlock your Mac to disarm — the actual app, photographed

What happened, and when

Nothing yet. Press Arm.

Meanwhile, in your pocket

What lands on your phone

A phone lock screen showing ntfy notifications: three photographs from the alarm, and a message from Yowl reading The lid was closed — a real alarm, blurred where the private topic is

The photographs arrive first, then the reason. You get them on a locked phone, from a machine that is already screaming somewhere else — and you can see who is holding it before you have unlocked anything.

Straight to you: Over ntfy, to a private topic nobody else has. No account, no server of ours in between.
Pictures, not just a ping: Including the ten seconds before the trigger, which is usually the shot that shows a face.
Says which trigger: "The lid was closed." "The laptop was moved." So you know what happened, not just that something did.

Also pinned here

What you can change

The Yowl settings panel: responses, saved photographs, grace period, phone alerts with a pairing code, start at login, passcode — the panel, blurred where the private topic is

Triggers: Charger on by default. Camera and lid sensor are opt-in; the lid one only appears on Macs that have the hinge sensor.
Responses: Siren, screen lock, photographs, phone alert — each switches off on its own, and arming is refused if nothing is left that could catch a theft.
Sensitivity: A live motion score at your own desk, so you can see whether your background defeats the detection before trusting it.
Grace period: None by default. The siren fires the instant the charger is pulled.
Phone alerts: Paired by scanning a code, with different paths for iPhone and Android — only Android can open the ntfy app from a scan.
Passcode: Not required. Unlocking your Mac is the disarm.

This page is a walkthrough, not the app. The photographs are the shipping interface and the timings are the real ones — the volume really is taken back every second, the photographs really do reach ten seconds back. A web page cannot hold your camera or make your Mac scream, so the sound and the lock are written down rather than performed.

Download How it tells a thief from a passer-by