Web FAQ

Contents

Is the web version of Flutter ready for production?

As of the 1.9 release, the web version of Flutter is available as a technical preview on the master channel. Web support has been added to the main Flutter repo, but is missing features and has known performance issues. We don’t recommend deploying a web app to production.

How do I migrate a web app built using the flutter_web repo to the flutter repo?

See Upgrading from package:flutter_web to the Flutter SDK.

How do I create an app that also runs on the web?

See building a web app with Flutter.

Does hot reload work with a web app?

No.

Can I use Flutter plugins?

Not yet.

How do I file an issue about web support?

You can file an issue on the main Flutter repo. Make sure that “web” is included in the title.

How do I refresh the app running in the browser?

You can either use the browser’s refresh button, or you can enter “R” in the console where “flutter run -d chrome” is running.

Can I build, run, and deploy web apps in any of the IDEs?

You can select Chrome as the target device in Android Studio/IntelliJ and VS Code if you are using the latest master channel of Flutter and have enabled web support. To enable support, run the following in the terminal:

flutter config --enable-web

You need only run this once. This command modifies (or creates) the ~/.flutter_settings file (on Mac/Linux) with the following:

{
  "enable-web": true
}

If the IDE is already running, restart it. The device pulldown should now include the Chrome (web) option.

What version of the IDE and corresponding Flutter plugin is required?

Because web support is in active development, we recommend that you use the latest version of your IDE, and the latest version of the Flutter and Dart plugins.

How do I build a responsive app for the web?

See Creating responsive apps.

Can I use dart:io with a web app?

No. The file system is not accessible from the browser. For network functionality, use the http package. Note that security works somewhat differently because the browser (and not the app) controls the headers on an HTTP request.

How are forward and backward buttons presented in the web UI?

The browser’s back button is supported for web apps. The forward button is not yet enabled. For more information, see Issue 32248.

How does copy/paste work?

Copy/paste works on mobile. If you encounter problems, please file an issue.

How do I embed a Flutter web app in a web page?

You can embed a Flutter web app, as you would embed other content, in an iframe tag of an HTML file. In the following example, replace “URL” with the location of your hosted HTML page:

<iframe src="URL"></iframe>

Implementing CORS

Web applications have special security restrictions. If you experience problems, check that the web server you are accessing is setting CORS headers that accept requests from the domain hosting your Flutter app.

How do I avoid JavaScript lockout with CORS?

TBD

How do I debug a web app?

Use Flutter DevTools for the following tasks:

Use Chrome DevTools for the following tasks:

How do I test a web app?

Use the normal widget tests.

Driver tests are not yet supported.

How do I internationalize a web app?

TBD

How do I deploy a web app?

See Preparing a web app for release.

Does Platform.is work on the web?

Not currently.

How can I compare notes others who are playing with this feature?

Check out the #web discussion board on Discord. Flutter engineers routinely read and respond on Discord.