The following table compares the features of the above graph databases.

The following is a list of several well-known graph database projects:

Neo4j is the most popular graph database.

Neo4j is an open-source graph database, implemented in Java.

By definition, a graph database is any storage system that provides index-free adjacency.

A new kind of navigational databases has recently emerged, the Graph databases.

Even if it is a document-based database, the relationships are managed as in graph databases with direct connections between records.

AllegroGraph is a closed source Graph database, an emerging category of databases.

Graph databases are based on graph theory.

Titan - A distributed, disk-based graph database developed by Aurelius.

Gremlin - an open-source graph programming language that works over various graph database systems.

Survey of graph database models.

In contrast with a Relational database, a graph database considers each stored item to have any number of relationships.

Gremlin works over those graph databases that implement the Blueprints property graph data model.

He is working for Neo Technology, the developer of the open-source graph database Neo4j.

Graph databases employ nodes, properties, and edges.

FlockDB is an open source distributed, fault-tolerant graph database for managing data at webscale.

DEX is a high-performance and scalable graph database management system written in C++.

Graph databases allow even more general structure than a network database; any node may be connected to any other node.

Graph database - uses graph structures with nodes, edges, and properties to represent and store data.

DEX is a graph database.

The sones graph database is able to store and retrieve unstructured properties in any node of the graph.

Other graph-like queries can be performed over a graph database in a natural way (for example graph's diameter computations or community detection).

InfiniteGraph - a commercially available distributed graph database that supports parallel load and parallel queries.

Graph databases like the sones GraphDB address the paradigm of the index-free adjacency.