The RPC Service allows for both sending transactions to the network and for querying state from the network. It is used by the akash command-line tool when using an akash tx command or akash query command.
The RPC Service is configured in the [rpc] section of ~/.akash/config/config.toml.
By default, the service listens on port 26657, but this can also be changed in the [rpc] section of config.toml.