Neo4j is a labelled, property graph database with a native engine that is targeted at operational and hybrid operational/analytic use cases. It is ACID compliant and supports immediate consistency. Most users employ Cypher or OpenCypher (the open source version), which is the declarative language developed by Neo4j, though other languages such as Gremlin are supported. OpenCypher is widely used within the graph community and it is also being deployed within several open source projects including Cypher for Apache Spark, and Cypher for Gremlin, as well as in research projects like InGraph for streaming queries.
This paper has been superseded by Neo4j (2020) (September, 2020)