A working understanding of Autodesk Revit Architecture, Autodesk Revit Structure or Autodesk Revit MEP 2016
An installation of an Autodesk Revit-based product, including the Software Development Kit
MS Visual Studio 2012 Express Edition (C# or VB.NET). Microsoft Visual Studio 2012 Professional is recommended, though, as Express editions do not support DLL debugging. Alternatively, you can use the built-in SharpDevelop development environment in Revit.
Some experience in a .NET based development language (Autodesk Revit API examples are provided in C# and Visual Basic.NET.)