The Ethereum node provides the JSON RPC interface, which is used by libraries such as Web3, as well as applications directly. The goal is to implement an interface that will work with requests and responses of a similar format. This is necessary to facilitate the migration of applications from the Ethereum platform to Echo.
In Echo JSON RPC implemented via additional plugin that enables with help of --plugins=ethrpc. If you enables plugin, you must also specify endpoint that webserver should listen with option --ethrpc-endpoint, for example --ethrpc-endpoint=0.0.0.0:8092. Plugin starts a webserver and binds implemented api on every connection. That api implements described methods converting Echo data format to specified one.