JSON Cheat Sheet

A quick reference for JSON syntax, data types, escape sequences, and common patterns. Copy-paste ready.

JSON Data Types

String

"hello world"
"line one\nline two"
"path: C:\\Users\\file"

Number

42
3.14
-17
1.0e10

Boolean

true
false

Null

null

Array

[1, 2, 3]
["a", "b", "c"]
[{"id": 1}, {"id": 2}]
[]

Object

{
  "name": "Alice",
  "age": 30,
  "active": true
}

Escape Characters

Sequence	Character	Example
`\\n`	Newline	`"line1\nline2"`
`\\t`	Tab	`"col1\tcol2"`
`\\\\`	Backslash	`"C:\\path"`
`\\"`	Double quote	`"say \"hi\""`
`\\/`	Forward slash	`"a\/b"`
`\\b`	Backspace	`"back\bspace"`
`\\f`	Form feed	`"form\ffeed"`
`\\r`	Carriage return	`"line\r\n"`
`\\uXXXX`	Unicode	`"\u00e9" (accent e)`

Common JSON Patterns

Config File

{
  "database": {
    "host": "localhost",
    "port": 5432,
    "name": "myapp",
    "ssl": true
  },
  "logging": {
    "level": "info",
    "format": "json"
  }
}

API Response

{
  "status": 200,
  "data": {
    "users": [
      { "id": 1, "name": "Alice", "email": "alice@example.com" },
      { "id": 2, "name": "Bob", "email": "bob@example.com" }
    ],
    "total": 2,
    "page": 1
  },
  "meta": {
    "requestId": "abc-123",
    "timestamp": "2024-01-15T10:30:00Z"
  }
}

package.json Structure

{
  "name": "my-app",
  "version": "1.0.0",
  "description": "A sample project",
  "main": "index.js",
  "scripts": {
    "dev": "next dev",
    "build": "next build",
    "start": "next start",
    "test": "vitest"
  },
  "dependencies": {
    "next": "^15.0.0",
    "react": "^19.0.0"
  },
  "devDependencies": {
    "typescript": "^5.0.0"
  }
}

JSON vs YAML vs XML

Feature	JSON	YAML	XML
Readability	Good	Excellent	Moderate
Verbosity	Low	Very low	High
Comments	No	Yes (#)	Yes (<!-- -->)
Data types	6 types	Rich (dates, etc.)	Strings only
Parsing speed	Fast	Moderate	Slow
Native in JS	Yes	No (library)	No (DOMParser)
Use case	APIs, configs	DevOps, configs	Enterprise, docs

Got some JSON to validate or format?

Validate Your JSON →