Common Data Model Builder (cdmb) The Common Data Model Builder (cdmb) is a Python library that facilitates building data models for projects with a defined structure. The library offers two ways to generate data models: using code or using a graphical interface. The library facilitates completing the project's metadata, including the cohort's definition, the entities and the validation rules of the data model. The cdmb assists a user in systematically generating a reproducible folder structure of the research project as a Research Object (RO) easily implemented in as part of a deployable workflow.