The original IDL version of the SWPC_CAT tool was developed by George Millward and Vic Pizzo at NOAA Space Weather Prediction Center (SWPC). It is the primary tool being used by NOAA SWPC in measuring key parameters of a Coronal Mass Ejection (CME) as it emerges from the solar corona. Please see their README [PDF] for more detailed information about the original tool.
This SWPC_CAT_Web Tool is an online version of the original SWPC_CAT being developed and maintained by the Community Coordinated Modeling Center (CCMC) at NASA. The web version of SWPC_CAT is written in Python.
NASA Open Source Project
Source code for SWPC_CAT_Web tool (the python version) is available on this NASA public GitHub project under a permissive NASA open source license.