On Mac OS X, the Factor UI offers additional features which integrate with this operating system.

First, a standard Mac-style menu bar is provided, which offers the bare minimum of what you would expect from a Mac OS X application.

Dropping a source file onto the Factor icon in the dock runs the source file in the listener.

If you install Factor.app in your Applications folder, then other applications will be able to call Factor via the System Services feature. For example, you can select some text in TextEdit.app, then invoke the TextEdit -> Services -> Factor -> Evaluate Selection menu item, which will replace the selected text with the result of evaluating it in Factor.