Which GUI library is used to develop Mozilla Firefox?

Question

Which GUI library is used to develop Firefox?

Qt? GTK+? Windows native?

Sunda

Answer 1

Firefox uses a number of GUI toolkits, including the native Windows one, as well as GTK+ for X platforms. Sadly, there is no official support for Qt.

Luella

"Sadly, it doesn't yet support Qt." The link you provided says exactly the opposite - that Mozilla's QT back-end is available and used in some custom builds of Mozilla. There is no need to use it in binaries distributed because more native back-ends are available and probably considered more suitable (functional/fast/natural). – Neocene

@Serge: Thanks, I updated my post to reflect official support. Re "more native back-ends are available": on KDE, Qt is "more native" than GTK+ (or to put it differently, unless you have a GTK+ engine that emulates the look of your current KDE look and feel, your GTK+ apps will look fugly). I'd love to have an officially-supported Qt build to use. – Luella

Answer 2

I heard that firefox is using their own GUI based off of XML and its called XUL. At least that's what it sounds like if your read their articles on XUL.

Gynaecomastia

Answer 3

Since 2019, the Firefox UI is made using Web Components: https://briangrinstead.com/blog/firefox-webcomponents/

Licastro