Very Basic ESOA question

I am a REAL newbie to ESOA. So my question is very basic.

I am looking to develop an application that makes a web call using SOAP or XML to a service within the SDN ES Workplace. I don't care what it does there except I want it to be meaningful, like retrieiving a list of customers or vendors or GL balances, or whatever. The application making a web call would not have any SAP software installed on it. No SAPGUI, No Visual Composer, nothing from SAP. It's just a pure web client that can make a SOAP and/or XML call.

So, first of all is that even technically possible? Is that what the ES Workplace all about?

Thanks