This app was mentioned in 2 comments, with an average of 1.50 upvotes
I use the app Human https://play.google.com/store/apps/details?id=co.human.android
It does passive activity tracking (compares against people in your area) but also has a notification setting for "Inactivity Nudges" where you can set it to remind you to move after sitting for a certain amount of time! I'm a programmer too and found it useful.