FastRPC is a RPC (Remote Procedure Call) protocol based on the XML-RPC which uses binary format for data serialization. It uses HTTP as transport protocol as the XML-RPC does. FastRPC is also an implementation of this protocol as C++ library and Python and PHP4 modules built with this library.
The library supports both protocols due to FastRPC's full data compatibility with the XML-RPC. Data format is negotiated via the HTTP content negotiation.
The fastrpc Python module is compatible with the xmlrpclib module. It's very simple to port project from xmlrpclib to fastrpc.