“jsonrpc-conduit implements the basic building block of a JSON-RPC 2.0 server.
It provides a Conduit that consumes RPC requests and invokes user-provided functions to handle them. Conversion of values to and from JSON is almost completely automatic thanks to the aeson library.

The JSON-RPC conduit is generic with respect to the channel used to exchange data with the client. It can use a network connection or, for example, the standard input / ouput of a process. The latter is demonstrated by the jsonrpc-conduit-demo executable, which can be compiled using the demo flag.” – http://hackage.haskell.org/package/jsonrpc-conduit-0.2.5