GXtest 4 is included inside GeneXus IDE, you can check it by going to the "Test" option on the menu bar:
If you don't have it installed already, there are several GXtest versions for the different versions of GeneXus, so it is necessary to install a compatible version.
GXtest Recorder is a Chrome extension that allows you to record and playback user actions on any GeneXus web application. You can find it in the Chrome Store.
GXtest has both free and licensed features. See the details about the license model.