BSON


BSON is a computer data interchange format. The name "BSON" is based on the term JSON and stands for "Binary JSON". It is a binary form for representing simple or complex data structures including associative arrays, integer indexed arrays, and a suite of fundamental scalar types.
BSON originated in 2009 at MongoDB. Several scalar data types are of specific interest to MongoDB and the format is used both as a data storage and network transfer format for the MongoDB database, but it can be used independently outside of MongoDB.
Implementations are available in a variety of languages such as C, C++, C#, D, Delphi, Erlang, Go, Haskell, Java, JavaScript, Julia, Lua, OCaml, Perl, PHP, Python, Ruby, Rust, Scala, Smalltalk, and Swift.

Data types and syntax

BSON has a published specification. The topmost element in the structure must be of type BSON object and
contains 1 or more elements, where an element consists of a field name, a type, and a value. Field names are strings. Types include:
An important differentiator to JSON is that BSON contains types not present in JSON and offers type-strict handling for several numeric types instead of a universal "number" type. For situations where these additional types need to be represented in a textual way, MongoDB's Extended JSON format can be used.

Efficiency

Compared to JSON, BSON is designed to be efficient both in storage space and scan-speed. Large elements in a BSON document are prefixed with a length field to facilitate scanning. In some cases, BSON will use more space than JSON due to the length prefixes and explicit array indices.

Example

A document such as will be stored as:

Bson:
\x16\x00\x00\x00 // total document size
\x02 // 0x02 = type String
hello\x00 // field name
\x06\x00\x00\x00world\x00 // field value
\x00 // 0x00 = type EOO