MongoDB

Mongodb is an open-source, document oriented database. It is the most popular NoSQL database and allows developers to store data in a flexible and scalable way. It stores data in JSON-like documents with dynamic schemas. The data model of Mongodb enables developers to represent hierarchical structures such as trees or graphs in a natural way.
MongoDB is designed to be fast and efficient for handling large amounts of data, and provides high availability with robust fault tolerance.It is written in C++ and has bindings to numerous programming languages such as Java, Python, Objective-C, Ruby, Go, and NodeJS. It has been used to build many popular web applications including Twitter, LinkedIn, eBay and Craigslist.