Flutter’s web support enables complex standalone web apps that are rich with
graphics and interactive content to reach end users on a wide variety of
devices.

Web support for Flutter provides a browser-based delivery model for existing
Flutter mobile apps.

Not every HTML scenario is ideally suited for Flutter at this time. 
For example, text-rich, flow-based, static content such as blog articles
benefit from the document-centric model that the web is built around,
rather than the app-centric services that a UI framework like Flutter
can deliver. However, you can use Flutter to embed interactive
experiences into these websites.

For a glimpse into how to migrate your mobile app to web, see
the following video:

Resources

The following resources can help you get started:

To add web support to an existing app, or to create a
new app that includes web support, see
Building a web application with Flutter.