Neo4j is a graph database management system developed by Neo4j, Inc. Described by its developers as an ACID-compliant transactional database with native graph storage and processing, Neo4j is the most popular graph database according to DB-Engines ranking, and the 22nd most popular database overall.
Neo4j is available in a GPL3-licensed open-source "community edition", with online backup and high availability extensions licensed under a closed-source commercial license. Neo also licenses Neo4j with these extensions under closed-source commercial terms.
Neo4j is implemented in Java and accessible from software written in other languages using the Cypher query language through a transactional HTTP endpoint, or through the binary "bolt" protocol.
Version 1.0 was released in February 2010.
Neo4j version 2.0 was released in December 2013.
Neo4j version 3.0 was released in April 2016.
In November 2016 Neo4j successfully secured $36M in Series D Funding led by Greenbridge Partners Ltd.
In November 2018 Neo4j successfully secured $80M in Series E Funding led by One Peak Partners and Morgan Stanley Expansion Capital, with participation from other investors including Creandum, Eight Roads and Greenbridge Partners.
New layout of the property stores, Upgraded to Lucene version 3.5
Pulled out Gremlin as separate plugin to support different versions
Query plan visualization
Spring Data Neo4j 4.0, Neo4j-Docker Image, Windows Powershell Support, Mac Installer, and Launcher
Neo4j IBM POWER8 CAPI Flash, User and role-based security and directory integrations
Query Monitoring, Kerberos Encryption, Clustering on CAPI Flash, Schema constraints,
new indexes and new Cypher editor with syntax highlights and autocompletion
Schema-based security and Role-Based Access Control, Role and user management capabilities,
Sharding and federated access, A new neo4j:// scheme
Neo4j comes in 2 editions: Community and Enterprise. It is dual-licensed: GPL v3 and a commercial license. The Community Edition is free but is limited to running on one node only due to the lack of clustering and is without hot backups.
The Enterprise Edition unlocks these limitations, allowing for clustering, hot backups, and monitoring. The Enterprise Edition is available under a closed-source Commercial license.
In Neo4j, everything is stored in the form of an edge, node, or attribute. Each node and edge can have any number of attributes. Both nodes and edges can be labelled. Labels can be used to narrow searches. As of version 2.0, indexing was added to Cypher with the introduction of schemas. Previously, indexes were supported separately from Cypher.
Neo4j is developed by Neo4j, Inc., based in the San Francisco Bay Area, United States, and also in Malmö, Sweden. The Neo4j, Inc. board of directors consists of Rod Johnson founder of the Spring Framework, Chris Barchak Partner at Conor Venture Partners, Magnus Christerson Vice President of Intentional Software Corp, Nikolaj Nyholm Partner at Sunstone Capital, Guarav Tuli Principal at Fidelity Growth Partners, and Johan Svensson CTO of Neo4j Inc.