Creating CAD tools for commercial FPGAs is a difficult task. Closed proprietary device databases and unsupported interfaces are largely to blame for the lack of CAD research found on commercial architectures versus hypothetical architectures. This paper formally introduces RapidSmith, a new set of tools and APIs that enable CAD tool creation for Xilinx FPGAs. Based on the Xilinx Design Language (XDL), RapidSmith provides a compact, yet, fast device database with hundreds of APIs that enable the creation of placers, routers and several other tools for Xilinx devices. RapidSmith alleviates several of the difficulties of using XDL and this work demonstrates the kinds of research facilitated by removing such challenges.