NoSQL Databases

NoSQL databases refer to any database types that are not only relational. “NoSQL” stands for “not only SQL”.

Relational database is the most popular database type nowadays. Structure Query Language (SQL) is a language to manage data in a relational database. This is why NoSQL is the term used to referred to not only relational databases.

Types of NoSQL Databases

Types of NoSQL Databases:

  • Key-value stores
  • Document stores
  • Graph databases
  • Wide-column stores
  • Search stores
  • Multi-model stores

Key-value stores are key/value pairs.

Document stores are similar to key/value stores, but the value is much more complex and it is in the form of a document, like XML or JSON

Graph databases store data in graph format.

Wide-column stores are optimized for queries over large datasets, and instead of rows, they store columns of data together.

NoSQL Databases Solutions

No SQL databases solutions:

  • Key-value stores
    • Redis
    • Amazon Dynamo DB
    • Etcd
  • Document stores
    • Apache Couchbase
    • FerretDB
    • MongoDB
    • Firebase
  • Wide-column stores
    • Apache Cassandra
    • Apache HBase
    • Bigtable
  • Graph store
    • JanusGraph
    • Neo4j
    • Amazon Neptune
    • ArangoDB
  • Search
    • ElasticSearch
    • Algolia
    • Mellisearch
  • Multi-model
    • Azure Cosmo DB

Take into account that traditionally relational DB PostgreSQL also accepts some of these models.

Key-value Store Solutions

The most popular key-value databases are Valkey, Redis and Amazon DynamoDB.

You can read more about key-value store solutions on this post.

Document Store Solutions

Document stores are specifically designed to handle JSON-like documents.

Some of the most popular document store databases are Apache CouchDB and MongoDB.

You can read more about document store solutions on this post.

Wide-column Store Solutions

Wide-column store solutions:

  • Apache Cassandra
  • Apache HBase
  • Bigtable
  • Apache Druid

Apache Cassandra

Apache Cassandra is a distributed wide-column store.

It is free and open source software (FOSS) under an Apache 2.0 license.

Apache Cassandra official website

Apache HBase

Apache HBase is a single-server wide-column store based on Bigtable.


Bigtable is a wide-column store.

As part of the Google Cloud portfolio, it is developed by American company Google.

Apache Druid

Apache Druid is FOSS under an Apache 2.0 license.

Graph Store Solutions

Graph store solutions:

  • JanusGraph
  • Neo4j
  • Amazon Neptune
  • ArangoDB
  • DGraph


JanusGraph is developed by The Linux Foundation.

It is FOSS under an Apache 2.0 license.


Neo4j is a graph store database.

It is source-viewable software under a GPLv3 license with a Commons Clause.

Amazon Neptune

Amazon Neptune is a graph store database.

Amazon Neptune official website


ArangoDB is a graph store database.

It is source-viewable under a BSL (Business Source License) 1.1.




  • OpenSearch
  • ElasticSearch
  • Algolia
  • Mellisearch


  • OrientDB
  • Azure Cosmos DB
  • FaunaDB
  • Couchbase Server


OrientDB is a multi-model database that combines the features of graph databases and document databases. It supports SQL-like queries, graph traversals, and ACID transactions.

Azure Cosmos DB

Azure Cosmos DB offers all types of NoSQL store.

Azure Cosmos DB official website



Couchbase Server

The community edition is released under an Apache 2.0.

Do not confuse it with document-based store CouchDB.

Official website

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External references

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