protobuf-rpc-pro is a Java developer library that provides an RPC layer for Google's Protocol Buffer services. It builds upon Netty for low-level NIO. Features include bidirectional RPC calls from client to server and from server to client. The client and server are equal communicating peers. TCP connection re-use / keep-alive, SSL encryption support, RPC call cancellation, timeout and a pluggable logging facility logging RPC call data in Protocol Buffer format are included.