Gtk – 4.0: The Broadway windowing system
Description: Reference for Gtk-4.0: The Broadway windowing system

#### The Broadway windowing system

## Using GTK with Broadway

The GDK Broadway backend provides support for displaying GTK applications in a web browser, using HTML5 and web sockets.

To run your application in this way, first run the broadway server, `gtk-broadwayd`, that ships with GTK:

    gtk4-broadwayd :5

The server expects the colon-prefixed display number as a commandline argument.

Then point your web browser at `http://127.0.0.1:8085`.

Once the Broadway server is running, you can start your applications like this:

    GDK_BACKEND=broadway BROADWAY_DISPLAY=:5 gtk4-demo

Multiple applications can be presented in the same web browser window.

## Broadway-specific environment variables

### `BROADWAY_DISPLAY`

Specifies the Broadway display number. The default display is 0.

The display number determines the port to use when connecting to a Broadway application via the following formula:

    port = 8080 + display