A free, open-source extension that lets Revit users write automation scripts in Python, an alternative to Dynamo's visual node-based scripting. Where Dynamo's visual graphs are approachable for modelers without a coding background, pyRevit appeals to users who already know or want to learn Python - the two aren't mutually exclusive, and some studios use Dynamo for quick one-off graphs and pyRevit for maintaining a shared library of reusable custom tools across a whole office.