This tutorial is not an introduction to Flutter itself. There are plenty of articles, videos and several books available online with simple introductions that will help you learn the basics of Flutter. Instead, we’ll be covering the following two objectives: The current state of Flutter non-mobile development and how you can run Flutter code in the browser, on a desktop or laptop computer; How to create responsive apps using Flutter, so that you can see its power — especially as a web framework — on full display, ending with a note about routing based on URL.

https://www.smashingmagazine.com/2020/04/responsive-web-desktop-development-flutter/