This document discusses the development of an open-source application called OpenStudyBuilder that was built using Neo4j graph database. OpenStudyBuilder has three main components - a clinical metadata repository, a web application interface, and an API layer. It applies domain-driven design principles to model complex clinical study data. Some challenges discussed include performance issues with the Neo4j ORM library, how to present graph data in tables, changing data models over time which requires data migrations, and potential limitations for non-profit or smaller users due to reliance on Neo4j Enterprise features. In summary, the document outlines how a Neo4j database was used as the data store for an enterprise clinical study specification application to effectively model