Lua Client

This client provides functionality to interact with a kRPC server from programs written in Lua. It can be installed using LuaRocks or downloaded from GitHub.

Installing the Library

The Lua client and all of its dependencies can be installed using luarocks with a single command:

luarocks install krpc

Using the Library

Once it’s installed, simply require 'krpc' and you are good to go!

Connecting to the Server

To connect to a server, use the krpc.connect() function. This returns a connection object through which you can interact with the server. For example to connect to a server running on the local machine:

local krpc = require 'krpc'
local conn = krpc.connect('Example')

This function also accepts arguments that specify what address and port numbers to connect to. For example:

local krpc = require 'krpc'
local conn = krpc.connect('Remote example', '', 1000, 1001)

Interacting with the Server

Interaction with the server is performed via the client object (of type krpc.Client) returned when connecting to the server using krpc.connect().

Upon connecting, the client interrogates the server to find out what functionality it provides and dynamically adds all of the classes, methods, properties to the client object.

For example, all of the functionality provided by the SpaceCenter service is accessible via conn.space_center and the functionality provided by the InfernalRobotics service is accessible via conn.infernal_robotics.

Calling methods, getting or setting properties, etc. are mapped to remote procedure calls and passed to the server by the lua client.

Streaming Data from the Server

Streams are not yet supported by the Lua client.


connect([name=nil][, address=''][, rpc_port=50000][, stream_port=50001])

This function creates a connection to a kRPC server. It returns a krpc.Client object, through which the server can be communicated with.

  • name (string) – A descriptive name for the connection. This is passed to the server and appears, for example, in the client connection dialog on the in-game server window.
  • address (string) – The address of the server to connect to. Can either be a hostname or an IP address in dotted decimal notation. Defaults to ‘’.
  • rpc_port (number) – The port number of the RPC Server. Defaults to 50000.
  • stream_port (number) – The port number of the Stream Server. Defaults to 50001.
class Client

This class provides the interface for communicating with the server. It is dynamically populated with all the functionality provided by the server. Instances of this class should be obtained by calling krpc.connect().


Closes the connection to the server.


The built-in KRPC class, providing basic interactions with the server.

Return type:krpc.KRPC
class KRPC

This class provides access to the basic server functionality provided by the KRPC service. An instance can be obtained by calling krpc.Client.krpc. Most of this functionality is used internally by the lua client and therefore does not need to be used directly from application code. The only exception that may be useful is:


Gets a status message from the server containing information including the server’s version string and performance statistics.

For example, the following prints out the version string for the server:

local krpc = require 'krpc'
local conn = krpc.connect()
print('Server version = ' .. conn.krpc:get_status().version)

Or to get the rate at which the server is sending and receiving data over the network:

local krpc = require 'krpc'
local conn = krpc.connect()
local status = conn.krpc:get_status()
print(string.format('Data in = %.2f KB/s', status.bytes_read_rate/1024))
print(string.format('Data out = %.2f KB/s', status.bytes_written_rate/1024))