You already know how to build mobile apps with Flutter, and, therefore, you also already know how to build beautiful, engaging, interactive web sites, as the principles for developing web apps with Flutter for the web are mostly the same. You still use Dart, widgets, libraries, and manage the state of your apps in the same way. There are some features still missing, such as hot reload, and some web-specific limitations, such as writing files on a disk, but you'll find that most of the great reasons for using Flutter are also valid for the web.