The Zend\Server family of classes provides functionality for the various server classes, including Zend\XmlRpc\Server and Zend\Json\Server. Zend\Server\Server provides an interface that mimics PHP 5's SoapServer class; all server classes should implement this interface in order to provide a standard server API.
The Zend\Server\Reflection tree provides a standard mechanism for performing function and class introspection for use as callbacks with the server classes, and provides data suitable for use with Zend\Server\Server's getFunctions() and loadFunctions() methods.