Utilizing our Server Public API: http://www.servoy.com/docs/public-api/index.html you can create client-side and server-side plugins.
Creating a client side plugin is very easy. For people unfamiliar with Eclipse, there is an example at http://forum.servoy.com/viewtopic.php?t=5812 which shows a simple client-side plugin.
In addition, you have the ability to create server-side plugins. With a server-side plugin, a client can initiate a call to the server and have the server perform some processing and then return the result back to the client. Our open-souce mail plugin is another example of a server-side plugin.
I have attached some example code of a very simple server-side Hello World plugin.