In this chapter you will find some links and comments on GUIs for ngspice offered from other projects and on the integration of ngspice into a circuit development flow. The data given rely mostly on information available from the web and thus is out of our control. It also may be far from complete. For a list of actual links with more than 20 entries please have a look at the ngspice web pages. Some open source tools are listed here. The GUIs MSEspice and GNUSpiceGUI help you to navigate the commands to need to perform your simulation. XCircuit and the GEDA tools gschem and gnetlist offer integrating schematic capture and simulation. KiCAD offers a complete design environment for electronic circuits.