“The app takes three seconds to open” is a complaint, not a measurement. Three seconds from what — the tap, the process spawning, the engine coming up, or the moment your main() runs? Each of those is a different problem with a different fix, and optimising the wrong one is how teams spend a sprint moving startup from 2.9 s to 2.8 s. Cold start in a Flutter app has four phases, and they are separable. The four phases 1. Process launch. The OS creates the process, loads the executable and its shared libraries, and hands control to the platform runner. Nothing in your Dart code affects this. What does affect it is binary size (see the app size discussion) and, on Android, the number of libraries to link. 2. Engine initialisation. The Flutter engine starts, the Dart VM comes up, and — in release builds — the AOT snapshot is mapped in. Plugin registration happens on the platform side here. 3. Dart main() to runApp() . Your code. This is the phase you control completely, and the o...