What Are the Properties of a Valid JSON?

Quick Reference: Valid JSON Must

✓Begin with an object or array []
✓Use double quotes for strings
✓Separate elements with commas
✓Use valid data types only

1. Basic Structure

A valid JSON document must start with either an object (denoted by curly braces ) or an array (denoted by square brackets []). This is a fundamental rule that forms the foundation of JSON structure.

Valid Examples:

// Valid object
{
  "name": "John Doe",
  "age": 30
}

// Valid array
[
  "apple",
  "banana",
  "orange"
]

2. Data Types

JSON supports six specific data types. Understanding these types is crucial for working with JSON:

String

Must be enclosed in double quotes

"Hello, World!"

Number

Integer or floating-point

42, 3.14, -1

Boolean

True or false values

true, false

Null

Represents no value

null

Array

Ordered list of values

["red", "green", "blue"]

Object

Collection of key-value pairs

{"key": "value"}

3. Common Validation Rules

Property Names

Must be enclosed in double quotes
Must be unique within an object
Can contain any valid string characters

String Values

Must use double quotes (not single quotes)
Special characters must be escaped with backslash
Unicode characters are allowed

Numbers

Can be integer or floating-point
Scientific notation is allowed (e.g., 1e-10)
Leading zeros are not allowed
Plus sign (+) is not allowed

4. Common Mistakes to Avoid

✗
Using Single Quotes
Always use double quotes for strings and property names
✗
Trailing Commas
JSON doesn't allow a comma after the last element
✗
Using Comments
JSON format doesn't support comments
✗
Unquoted Property Names
Property names must be enclosed in double quotes

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