XML-RPC is a remote procedure call (RPC) protocol which uses XML to encode its calls and HTTP as a transport mechanism. also refers generically to the use of XML for remote procedure call, independently of the specific protocol.
XML-RPC permits programs to make function or procedure calls across a network.
XMLRPC uses the HTTP protocol to pass information from a client computer to a server computer.
XML-RPC uses a small XML vocabulary to describe the nature of requests and responses.
XML-RPC client specify a procedure name and parameters in the XML request, and the server returns either a fault or a response in the XML response.
XML-RPC parameters are a simple list of types and content – structs and arrays are the most complex types available.