Wikipedia (https://en.wikipedia.org/wiki/John_gruber https://en.wikipedia.org/wiki/John_gruber) says he has a BS in compsci and worked at Bare Bones Software an

Wikipedia (https://en.wikipedia.org/wiki/John_gruber https://en.wikipedia.org/wiki/John_gruber) says he has a BS in compsci and worked at Bare Bones Software and Joyent before he started doing Daring Fireball and writing as a full time thing, so it looks like he has at least some experience in the software developer trenches.