This Sticky will be used over time to provide information on Tools Programming. It is intended to help those who may be new to developing add-on programs for FS. It is in the form of a Q&A FAQ and will be added to over time. Q. What is the best programming language to develop FS Add-ons? A. There isn't one. Add-ons can be developed in any language from C thru Delphi to VB.NET and C#. In many cases it will come down to the degree of interaction that is needed with FS and the personal preference of the developer. In FS9 the main way to do that is through FSUIPC and there are SDK examples of how to interact in most of the common programming languages. In FSX the expectation is that developers will use SimConnect to interact. The SDK for SimConnect provides access via C++ or C#, although the managed library can be accessed from any dotNET language such as VB.NET or Java.