http is a bad protocol for internal services due to arbitrary length text headers with big parsing overhead and lack of multiplexing of packets per connection by default. Even FastCGI is much better choice.
Erlang's messaging protocol, Protocol Buffers, Msgpack and other carefully serializing solutions trying to reduce parsing and communication overheads.
ZeroMQ seems like natural choice for the core of so-called messaging middleware, because, well, it's what it was designed for.)
And, of course, avoiding JVM leads to great reduction of resource wasting.
Erlang's messaging protocol, Protocol Buffers, Msgpack and other carefully serializing solutions trying to reduce parsing and communication overheads.
ZeroMQ seems like natural choice for the core of so-called messaging middleware, because, well, it's what it was designed for.)
And, of course, avoiding JVM leads to great reduction of resource wasting.