Difference between Cassandra and CouchDB

1. Cassandra :
Cassandra is a free and open-source, distributed, wide column store, NoSQL database management system. It was developed by Apache Software foundation and initially released on July 2008. Cassandra is designed to handle large amounts of data across many commodity servers, providing high availability with no single point of failure.

2. CouchDB :
Apache CouchDB is an open-source document-oriented NoSQL database that uses multiple formats and protocols to store, transfer, and process its data, it uses JSON to store data, JavaScript as its query language using MapReduce, and HTTP for an API. It was developed by Apache Software Foundation and initially released in 2005. It is written in Erlang.

Difference between Cassandra and CouchDB :

S.NO.	Cassandra	CouchDB
1.	Developed by Apache Software foundation and released on July 2008.	Developed by Apache Software Foundation and initially released in 2005.
2.	Cassandra is written in Java language.	CouchDB is written in Erlang language.
3.	The primary database model for Cassandra is Wide Column Store.	The primary database model for CouchDB is Document Store.
4.	Cassandra supports predefined datatypes such as float, date, number, etc.	In CouchDB there is no predefined datatypes.
5.	Secondary indexes in Cassandra is restricted.	CouchDB does not supports Secondary indexes.
6.	Cassandra have SQL supports i.e it supports some SQL statements like DML, DDL, SELECT, etc.	CouchDB does not supports SQL.
7.	Cassandra supports Selectable Replication Factor replication method.	CouchDB supports Master-Slave Replication and Master-Master Replication replication methods.
8.	Cassandra provides both Eventual Consistency and Immediate Consistency methods to ensure consistency in a distributed system.	CouchDB provides Eventual Consistency method to ensure consistency in a distributed system.
9.	Server operating systems for Cassandra are BSD, Linux, OS X, Windows.	Server operating systems for CouchDB are Android, BSD, Linux, OS X, Solaris and Windows.
10.	Famous companies like GitHub, Hulu, Instagram, Reddit, The Weather Channel, etc uses Cassandra.	Famous companies like Akamai Technologies, Hothead Games, Inc., GenCorp Technologies, Vivint Solar, etc uses CouchDB.