Search really is your friend. There is no official documentation at this time.Although currently via the API you can only open a ticket, so documentation is really needed.This article would assist you with it: http://tmib.net/using-osticket-1812-apiThe API is supposed to be expanded and documentation will be forth coming once it has been.A member of the forums here also posted this thread with an unofficial guide:http://forum.osticket.com/d/discussion//unofficial-plugin-development-guide