Flutter Performance Profiling in the Real World

Shader jank, rebuild storms, and the profiling workflow we use before every App Store submission.

Profile on devices users own

Simulator smoothness lies. We profile on mid-tier Android hardware and older iPhones because that is where jank becomes churn. Establish a baseline scroll and navigation journey for every release candidate.

Flutter DevTools performance and CPU profilers are mandatory gates, not optional curiosities before App Store week.

Shader jank and warm-up

First-animation stutters often come from shader compilation. Impeller improved the iOS story, but you still need to exercise critical animations during startup warm-up where appropriate and avoid surprise shader-heavy effects on first paint.

Track frame build and raster times separately so you know whether the problem is layout or GPU.

Rebuild storms

Unnecessary rebuilds from broad InheritedWidgets, runaway setState, or giant build methods show up as build-phase spikes. Split widgets, use selective listeners, and prefer const constructors where they help.

RepaintBoundary can help — and can hurt if sprinkled blindly. Measure after each change.