JSON Formatter Guide - Format and Validate JSON

Understanding JSON

JSON (JavaScript Object Notation) is the lingua franca of web data. It’s used for APIs, configuration files, and data storage due to its simplicity and universal support.

JSON Syntax Rules

Basic Structure

{
  "key": "value",
  "number": 42,
  "boolean": true,
  "null": null,
  "array": [1, 2, 3],
  "object": {"nested": "value"}
}

Valid Data Types

• String: "text" (double quotes required)
• Number: 42, 3.14, -7, 1e10
• Boolean: true or false
• Null: null
• Array: [1, 2, 3]
• Object: {"key": "value"}

Invalid in JSON

• Single quotes: Use "text" not 'text'
• Trailing commas: [1, 2, 3,] is invalid
• Unquoted keys: Use {"key": 1} not {key: 1}
• Comments: JSON doesn’t support comments
• Undefined: Use null instead

Formatting JSON

Minified (Compact)

{"name":"John","age":30,"city":"NYC"}

Best for: Transmission, storage

Formatted (Pretty)

{
  "name": "John",
  "age": 30,
  "city": "NYC"
}

Best for: Reading, debugging, editing

Common JSON Errors

Missing Comma

❌ {"a": 1 "b": 2} ✅ {"a": 1, "b": 2}

Trailing Comma

❌ {"a": 1, "b": 2,} ✅ {"a": 1, "b": 2}

Single Quotes

❌ {'name': 'John'} ✅ {"name": "John"}

Unescaped Characters

❌ {"text": "Line 1 Line 2"} ✅ {"text": "Line 1\nLine 2"}

Working with JSON

In JavaScript

// Parse JSON string to object
const obj = JSON.parse('{"key": "value"}');

// Convert object to JSON string
const json = JSON.stringify(obj, null, 2);

In Python

import json

# Parse
data = json.loads('{"key": "value"}')

# Stringify
json_str = json.dumps(data, indent=2)

JSON vs Other Formats

Format Your JSON

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Conclusion

Working with JSON is a daily task for developers. Proper formatting makes debugging easier, while validation catches errors before they cause problems.