In OTRS 4, you don't need to install or buy it separately, it's already included. The documentation is here: http://otrs.github.io/doc/manual/admin/stable/en/html/genericinterface.html -- Christoph Am 18.03.2015 um 16:10 schrieb Arthur Grohe:

Hi!

anyone know how much the rest add-on is and where to get it? oh, and is it compatible with OTRS 3.3.x versions? and last but not least, can someone provide a link how to install / configure this?

Thank you very much! Greets, Arthur