I'm a developer and I sit about ten hours a day. My lower back has been going out on me for years. I also play basketball, and I tore my ACL last October, so this year has been surgery, physio, and even more chair than usual. My wife is an architect. Same laptop, same chair, same ten hours. We have a one year old, so "just train in the evening" is a fantasy. We built Mossy for the two of us, to kill the sitting, after deleting every break app we tried. They all failed the same way: the full screen break lands mid-sentence, you skip it, and a week later it's gone. So Mossy never blocks anything. It sits in the corner, wilts while you sit, and waits. Refusing a break is a normal way to use it, not a failure to correct. The second thing we needed was breaks that fit our own bodies. Mine needs hip and psoas work, hers doesn't, and no fixed stretch list was ever going to cover both. So you write one sentence and an AI writes each break from it. Your words decide what you do, and nothing in the app inspects what you asked for. Write "20 push-ups" or "teach me a Spanish word" and that is what you get. The key for that AI lives on a small relay, never in the app. The only things that leave your Mac are that one call and an anonymous daily ping you can switch off. No account, no tracking. It isn't medical advice, and the app says so itself. Free, native Swift, 1.4 MB, macOS 12+.

Mossy

A desk plant that wilts. You write what the break is.

A desk plant that wilts. You write what the break is.