JSON Data Types Explained with Examples

 If you are new to JSON, first read our complete beginner guide on What is JSON.

What is JSON? A Beginner-Friendly Guide

Introduction

If you already understand what JSON is, the next important step is learning about JSON data types. Data types define what kind of value a key can store inside a JSON object.

Understanding JSON data types is essential when working with APIs, web applications, and backend development.

What Are JSON Data Types?

JSON supports six main data types:

1. String
2. Number
3. Object
4. Array
5. Boolean
6. Null

Let’s understand each one with examples.

1️⃣ String

A string is a sequence of characters wrapped in double quotes.

Example:

{
  "name": "Suraj"
}

Important:

• Strings must be inside double quotes.

• Single quotes are not allowed in JSON.

2️⃣ Number

A number can be an integer or decimal.

Example:

{
  "age": 25,
  "price": 99.99
}

JSON does not differentiate between integers and floats.

3️⃣ Object

An object is a collection of key-value pairs inside curly braces { }.

Example:

{
  "person": {
    "name": "John",
    "age": 30
  }
}

Objects can contain other objects.

4️⃣ Array

An array stores multiple values inside square brackets [ ].

Example:

{
  "skills": ["HTML", "CSS", "JavaScript"]
}

Arrays can contain:

• Strings
• Numbers
• Objects
• Even other arrays

5️⃣ Boolean

A boolean represents true or false.

Example:

{
  "isStudent": true
}

Important:

• Boolean values are not in quotes.
• Must be lowercase: true or false

6️⃣ Null

The null type represents an empty or missing value.

Example:

{
  "middleName": null
}

Null is useful when a value is intentionally empty.

Complete JSON Example Using All Data Types

{
  "name": "Suraj",
  "age": 22,
  "isDeveloper": true,
  "skills": ["HTML", "CSS", "JavaScript"],
  "address": {
    "city": "Delhi",
    "country": "India"
  },
  "middleName": null
}

This example uses all six JSON data types together.

Why JSON Data Types Matter

When working with APIs:

• Data types help maintain structure.
• They ensure correct data handling.
• They prevent errors in applications.

Incorrect data types can break applications.

Conclusion

JSON supports six main data types: String, Number, Object, Array, Boolean, and Null. Understanding these types is essential for working with modern web applications and APIs.

Once you understand JSON data types, reading and creating JSON becomes much easier.