JavaScript Object Notation (JSON) is an open, human and machine-readable standard that facilitates data interchange, and along with XML is the main format for data interchange used on the modern web. JSON supports all the basic data types you’d expect: numbers, strings, and boolean values, as well as arrays and hashes.

Document databases such as MongoDB use JSON documents in order to store records, just as tables and rows store records in a relational database. Here is an example of a JSON document:

    '_id' : 1,
    'name' : { 'first' : 'John', 'last' : 'Backus' },
    'contribs' : [ 'Fortran', 'ALGOL', 'Backus-Naur Form', 'FP' ],
    'awards' : [
            'award' : 'W.W. McDowell Award',
            'year' : 1967,
            'by' : 'IEEE Computer Society'
        }, {
            'award' : 'Draper Prize',
            'year' : 1993,
            'by' : 'National Academy of Engineering'

A JSON database returns query results that can be easily parsed, with little or no transformation, directly by JavaScript and most popular programming languages – reducing the amount of logic you need to build into your application layer.

Binary JSON (BSON)

MongoDB represents JSON documents in binary-encoded format called BSON behind the scenes. BSON extends the JSON model to provide additional data types, ordered fields, and to be efficient for encoding and decoding within different languages.

MongoDB, BSON, and JSON

The MongoDB BSON implementation is lightweight, fast and highly traversable. Like JSON, MongoDB's BSON implementation supports embedding objects and arrays within other objects and arrays – MongoDB can even 'reach inside' BSON objects to build indexes and match objects against query expressions on both top-level and nested BSON keys. This means that MongoDB gives users the ease of use and flexibility of JSON documents together with the speed and richness of a lightweight binary format.

Read our MongoDB overview to learn more about these features.

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