Widget Previews shipped as experimental back in 3.35, and a lot of developers tried it once, found it slow, and went back to hot reload. Flutter 3.47 marks it stable , with local build caching and an abstract theming API that makes the feature worth a second look. If you build design systems, component libraries, or anything with more than three visual states, this changes your inner loop. The pitch is narrow and honest: the previewer renders individual widgets in isolation, without booting your app, navigating to the right screen, or faking the right state. That is a different job from hot reload, and it is the job hot reload has always been bad at. Starting the previewer From your IDE — Android Studio, IntelliJ, or VS Code — the previewer starts automatically; open the Flutter Widget Preview tab in the sidebar. From a terminal: flutter widget-preview start That launches a local server and opens a live preview environment in your browser. Builds are cached in a .widget_previe...