Open JSON File

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JSON Data Types

JSON data format is derived from the Javascript language. That is why datatypes that it uses are also derived from the Javascript.

Datatypes which JSON supports:

  • Boolean
  • Integer
  • Number
  • String
  • Object
  • Array
  • Null

In contrast with Javascript JSON cannot use following data types:

  • Function
  • Date
  • Undefined

Below we will review each of the supported types in detail.


Boolean data type can have two values: true or false. For example:

{ “complete”: true, “commited”: false }

Number and Integer

JSON schema located at defines two types which can define a numeric value: number and integer.

“Number” data type is a decimal (hexadecimal and octal is not supported) integer or floating-point data type. Integer defines any number with a zero fractional part.

 “salary”: 1500,
 “bonus”: 300.5


String data type represents a sequence of characters. String could contain zero or more characters from the Unicode character set.

“intro”: “hello world”


Array is a complex JSON data type which contains a sequence of elements which could be either of simple data type, or array, or object.

 “directions”: [“up”, “down”, “left”, “right”]


Object data type is a complex JSON data type which contains a set of key/value pairs. Keys should be strings and values could be of any data type supported by JSON.

“carspec”: {
 “engine”: “2.0L”,
 “doors”: 4,
 “automatic”: true


Null is used to identify missing or unknown data. Null is not actually a data type but a notation which defines a value outside of the range of values of the data type or unknown value.

 “location”: null