MongoDB is the most commonly used NoSQL database. MongoDB is based on the Document store data model and stores data as BSON (Binary JSON) documents. MongoDB provides a flexible schema-less storage format in which different records could have different fields, implying that no fixed data structure is applied. Field values have no data types associated with them and different fields could be of different data types. With the JSON format, hierarchies of data structures become feasible, and a field could store multiple values using an array. In this chapter we shall use a Docker image to run MongoDB in a Docker container. This chapter has the following sections.