A few years ago a friend who runs a small salon asked me to build her a booking app. Nothing fancy. A service list, a calendar, a confirmation screen and a reminder notification. I was proud of the Android version within three weeks. Then she mentioned, very casually, that half her customers used iPhones.

I remember staring at my screen for a good minute. It was not that the iPhone version was hard. It was that I had to build the whole thing again. Same list, same calendar logic, same validation rules, same bugs, just written in a different language by a slightly more irritated version of me. When the two apps finally shipped, the Android one rounded a button corner differently, and the iPhone one handled a cancelled booking in a way I had forgotten to match. My friend noticed both within a week.

That experience is what mobile app dev looked like for a long time, and it is the quiet reason Flutter app development has taken such a firm place in how modern teams build. This article is a set of field notes.…