Your posture is bad right now.
Your Mac already has a camera pointed at your face. Posture uses it to catch the slow slide forward, says one thing, and stops the moment you sit back.
macOS 14 Sonoma or later · Apple silicon · MIT licence
Detection
Notifications
Monitoring
The Camera page. The box is what it measured this frame; the dashed line is the height you calibrated. Drift past your tolerance and the verdict names the fix, then one banner follows.
The Stats page. This session's split and nothing more. Nothing is written to disk, so there is no history to leak.
The Settings page. How far is too far, how long before it speaks, how often it repeats. The same choices sit in the menu bar.
Inside the app
Almost all of it happens in the menu bar.
A square next to the clock, one banner when you drift, and a small mirror so you can see what it saw. The window you tried at the top of the page is behind all that, and you can go a month without opening it.
Posturenow
Bad posture for a minute. Sit back.
Questions
Reasonable suspicions, answered.
Is any video sent anywhere?
No. The app has no network entitlement at all, so macOS blocks it from making connections even if it tried. Frames are analysed in memory and dropped immediately.
Why is it free?
It is a menu bar app that compares two angles. Charging for it would mean building a licence server, a payment flow and an account system, three things that would each need the network access this app deliberately does not have. Free and MIT is the honest shape for it.
Does it work in bad lighting?
It needs enough light for macOS to find a face, roughly what you would need for a video call. In a dim room it reports that it cannot see you rather than guess.
Will it eat my battery?
It samples a few frames per minute rather than running a live video stream, and the work happens on the efficiency cores. When the lid is shut or no face is in frame, it stops sampling.
Can I use an external webcam?
It is designed around the built-in camera, since that sits at a known angle relative to the screen. External cameras that macOS exposes should work, but calibration matters more.
Windows or Linux?
Not planned. The pose detection leans on Apple’s Vision framework, which does the hard part on-device for free. Rebuilding that elsewhere would be a different project.
When can I download it?
Now. The download button on this page always serves the newest release: a signed and notarized DMG. Open it, drag Posture to Applications, and grant camera access when macOS asks. Every release also lives on the GitHub releases page with its changelog.