ArangoDB is a free and open-source native graph database system developed by ArangoDB Inc. ArangoDB is a multi-model database system since it supports three data models ( JSON documents, graphs, key/value) with one database core and a unified query language AQL (ArangoDB Query Language). ArangoDB is a NoSQL database system, but AQL is similar in many ways to SQL. AQL is mainly a declarative language and permits the combination of different data access patterns in a single query.