What is JSON?

What is JSON?

JSON (JavaScript Object Notation) is a lightweight data format for storing and exchanging structured data. It is readable for humans and easy for machines to parse.

JSON Syntax Rules

Basic Syntax Structure

• • JSON is made of key-value pairs such as "name": "John"

• • Keys must use double quotes

• • Items are separated by commas, without trailing commas

• • Objects use {} and arrays use []

• • Nested objects and arrays are supported

Common Mistakes

1. Comments are not allowed

1. Single quotes are invalid in JSON strings

1. Trailing commas are invalid

1. Keys must be strings

Core Data Types

JSON supports six core data types: String, Number, Object, Array, Boolean, and Null.

JSON vs XML

JSON is usually more compact and faster to parse than XML, making it a common choice for modern Web APIs.

Practical JSON Operations in JavaScript and Python

JavaScript

const jsonString = '{"name": "Alice", "age": 28, "city": "Beijing"}';
const obj = JSON.parse(jsonString);
console.log(obj.name);

const user = {
  name: "Bob",
  age: 32,
  email: "bob@example.com",
  isActive: true
};

const minified = JSON.stringify(user);
const pretty = JSON.stringify(user, null, 2);
console.log(minified);
console.log(pretty);

Python

import json

json_string = '{"name": "Alice", "age": 28, "city": "Beijing"}'
data = json.loads(json_string)
print(data['name'])

user = {
    "name": "Bob",
    "age": 32,
    "email": "bob@example.com",
    "is_active": True,
    "skills": ["Python", "JavaScript"]
}

json_output = json.dumps(user, ensure_ascii=False)
pretty_output = json.dumps(user, ensure_ascii=False, indent=2)
print(json_output)
print(pretty_output)

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Continue with JSON Tools

• • JSON Validator

• • JSON Beautifier

• • JSON to YAML Converter