Using GTK+ with Broadway 3 GTK Library Using GTK+ with Broadway HTML-specific aspects of using GTK+ 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, select the Broadway backend by setting GDK_BACKEND=broadway. Then you can make your application appear in a web browser by pointing it at http://127.0.0.1:8080. Note that you need to enable web sockets in your web browser. You can choose a different port from the default 8080 by setting the BROADWAY_DISPLAY environment variable to the port that you want to use. It is also possible to use multiple GTK+ applications in the same web browser window, by using the Broadway server, broadwayd, that ships with GTK+. To use broadwayd, start it like this: broadwayd :5 Then point your web browser at http://127.0.0.1:8085. Start your applications like this: GDK_BACKEND=broadway BROADWAY_DISPLAY=:5 gtk4-demo 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