Camera video and your sets stay on this device: the picture goes only into the body tracker in this browser, it is never recorded or uploaded, and there is no account. Only numbers are saved (reps, angles, times), so save a backup file now and then.
Camera form check and rep counter
Prop the phone up, step back and move. Formpad watches the set, counts the reps it can see, flags half reps and calls out one fix at a time.
Not medical advice. One camera sees the body in 2D, so it can miss a rounded back, knees caving in or a twist: keep an eye on yourself too. Stop if anything hurts.