There are many industrial robot manufacturers providing industrial robots with its controller and software. With safety and real-time operation concerns, these commercial robots have restrictive programming facilities. A few processes may run concurrently. Old style, imperative programming languages provided by robot manufacturers make software development difficult and expensive. This paper presents a software design based on server-client architecture in a modular form. At the server side, the controller of the robot manages the robot according to commands received from Ethernet connection. At the client side, the programmer may develop custom software by using robot API. It allows the user to manage robot by sending commands through the Ethernet connection. The design details and an application implemented by using Kawasaki 6-axis robot are given.