Which tool to choose
Two different jobs, two different tools. Don't choose at random.
If the problem is that you forget to sit up straight (you only notice when your neck hurts in the afternoon), you need continuous monitoring via webcam:
- On any PC → the Chrome extension from SitSense. It uses AI and the webcam to monitor posture in real time and give instant feedback when you slouch; it runs entirely in the browser. The extension is free, the full version costs $34.99/year. Working on the entire torso and not on a single back angle, it detects forward head, neck angle, trunk alignment and shoulder tilt from the laptop camera.
- On Mac, Windows or Linux, including desktop → SitApp. It runs outside the browser and is the only AI tracker that works on all desktop platforms.
- Mac only, willing to pay for total privacy → Posture Reminder AI. It costs $9.99/month, gives real-time posture alerts, has a privacy-first architecture (no data leaves the device) and works with all compatible Mac cameras. There's a full 24-hour free trial with no credit card.
If the problem is that you don't know how your workstation is set up (monitor too low? wrong chair?), you don't need an app that monitors: you need a one-time diagnosis. Use ChatGPT or Claude with a photo of the desk. It's free and takes five minutes.
The honest advice: do both. The photo analysis fixes the workstation, the app keeps you straight on the fixed workstation.
How to do it
Part 1 — Diagnosing the workstation with AI (5 minutes)
- Sit as you actually work, not posed. Ask someone to take a photo of you from the side, full-body, framing from the head down to the feet and including the desk, monitor, chair and keyboard. If you're alone, set the phone far away with the timer.
- Open ChatGPT (free is fine, image analysis is included) or Claude. Upload the photo.
- Paste this prompt:
You are an ergonomist. Analyze this photo of my workstation,
taken from the side while I'm sitting as I usually work.
Assess these points for me, one by one, saying for each whether it's correct
or what I need to change in practice (raise, lower, bring closer, move):
- monitor height relative to my eyes
- eye-to-screen distance
- elbow angle while typing
- position of shoulders and neck
- back support and lumbar support
- feet resting on the floor and knee angle
- position of keyboard and mouse
Give me a list of concrete actions ordered from the most important,
using only objects I already have or cheap do-it-yourself solutions.
Indicate the reference measurements in centimeters.
- Read the actions and apply the first one. Feedback: if the AI tells you "the monitor is too low, raise it by about 10 cm so the top edge reaches eye level", a stack of books under the screen is the immediate test. Do you already feel less tension on the neck? Then the diagnosis was right.
The parameters the AI should confirm for you (and that you can verify by hand) are these: when seated, the desk should be at a height that lets you keep your elbows at 90 degrees with your forearms parallel to the floor. The monitor should be at eye level, with the top of the screen at eye level or slightly below. The useful distance is that of an outstretched arm: the screen 50–70 cm from your face. Back straight against the seat, knees at 90 degrees (not crossed) and feet firmly on the floor.
Part 2 — Continuous monitoring with the webcam app (2 minutes of setup)
I'll take SitSense as an example because it's free and cross-platform via Chrome; with SitApp or Posture Reminder the concept is identical.
- In a browser, open the Chrome extensions store, search for the posture tracking extension and install it. Grant access to the webcam when prompted.
- Calibration: sit in the correct position (the one fixed in Part 1) and press the calibration button. The app records what your "straight" is. Between installation and calibration you're monitoring in under two minutes.
- Set the frequency of the alerts. On these apps it's adjustable; on Posture Reminder, for example, it goes from 1 to 60 minutes.
- Let it run in the background while you work. Feedback: the first time you slouch, the notification should reach you within a few seconds. If it doesn't, the webcam probably isn't framing you from the front (see below).
Concrete example
Marco, a developer working remotely, works 8 hours on a laptop resting directly on the desk. At the end of the day he has a stiff neck and a headache. He takes a photo from the side with the timer and gives it to ChatGPT with the prompt above.
The answer pinpoints the main culprit: the screen too low, which forces him to look down all day. It's the structural problem of the laptop, where screen and keyboard are a single piece: if you raise the screen the keyboard is too high, if you lower the keyboard the screen is too low. The solution indicated is the standard one: a laptop riser plus an external keyboard and mouse; in the minimal version, a stack of books under the laptop to raise the screen, plus an external mouse.
Marco doesn't have a stand, so he puts three books under the laptop and connects a USB keyboard he had in a drawer. Then he installs the SitSense extension, calibrates in the new position and sets an alert every 15 minutes. In the first two days he receives about ten notifications in the afternoon: it's proof that he was really slouching. After a week the notifications drop on their own and the evening headache disappears. Total cost: zero.
When it does NOT work (and how to fix it)
If the webcam doesn't frame you from the front
It's the most common limit of these apps. With a laptop placed to the side, the camera doesn't look at you directly and detection accuracy collapses. Fix: after raising the screen, position the laptop (or an external webcam) centered in front of you. If you use an external monitor, a USB webcam clipped above the screen solves it. The camera must see head and shoulders from the front.
If the AI invents measurements or misreads the photo
Visual analysis isn't infallible and can get proportions wrong. Don't trust the exact centimeters: use them as a starting point and verify with your body. The manual method that doesn't fail is one: measure your body in the real position in which you work. Sit with your elbows at 90°; the height at which your forearms naturally fall is the right height for the work surface. If the AI's measurements deviate a lot, trust the elbow.
If the app distracts you instead of helping you
If the notifications come too often they become noise and you ignore them. Raise the interval (for example from 5 to 20 minutes) and recalibrate: you probably recorded an already-tense position as "straight". Recalibrate relaxed and leaning against the backrest.
If posture doesn't improve anyway
No workstation, however perfect on paper, eliminates the damage of prolonged stillness. Add micro-breaks: one every 30–45 minutes, 30–60 seconds to get up and move. You can ask the AI to generate three desk stretching exercises for neck and shoulders, to do at the break.
A tip from someone who actually uses it
The trap is thinking the AI app does the work in your place. It doesn't: it only makes you aware. The real leap happens when you fix the workstation first (Part 1) and then turn on the monitoring (Part 2), not the other way around. If you calibrate the app on a wrong workstation, you teach it to consider "normal" a posture that hurts you. First the photo diagnosis, then the books under the monitor, then the calibration. In that order.
Frequently asked questions
Is the photo analysis on ChatGPT free?
Yes. Uploading an image and having it analyzed is included even in ChatGPT's free plan (and Claude's). You don't need the subscription for a workstation diagnosis. If the AI refuses because you're in the photo, crop out your face or specify in the prompt that you only want an ergonomic assessment of the posture, not an identification.
Which webcam app do I choose if I use neither Chrome nor Mac?
SitApp. It's the only AI tracker that runs outside the browser on Mac, Windows and Linux: if you're not on a Mac and don't want to go through Chrome, it's effectively your only option for real slouch detection.
Do these apps spy on my face all day?
No, and it's the most legitimate concern. On these tools the processing is local: the monitoring runs on the device, no image is saved, uploaded or shared, and after the initial subscription verification the detection works offline. The webcam feeds the algorithm on your computer, no video leaves toward a server. If you want maximum assurance, choose an app that works offline and check in the permissions that it doesn't have network access during use.
Is an AI app enough to solve back pain?
No, and it's the myth to debunk: the app corrects the habit, not the physical cause. It works as an alarm bell for slouching and tech neck and brings you back to correct posture before the damage accumulates, but it doesn't fix your back overnight. It must be combined with a correct workstation, movement breaks and, if the pain persists or is severe, with a visit to a physiotherapist. The AI is the reminder, not the doctor.