While REST architecture has been widely adopted for web services, the lack of standard formalism for their description prevents from implementations interoperability. The erocci framework, based on erlang/OTP platform, implements the OCCI specification for building interoperable, self-documented web services. Building a scalable web service is as simple as describing your application model in an XML document and choosing amongst existing data backend. It can be extended in various ways to adapt to data sources (database, 3rd party web services, DBUS APIs, etc.), protocols (HTTP, XMPP, etc.), authentication mechanisms, etc.