JSON Formatter & Validator

What is JSON?

JSON (JavaScript Object Notation) is the most popular data interchange format on the web. APIs return JSON. Config files use JSON. Databases (MongoDB, Firebase) store JSON. If you work with web tech, you read JSON daily.

JSON looks like JavaScript objects but is language-agnostic:

{
  "name": "Krishna Kumar",
  "age": 25,
  "skills": ["PHP", "React", "Node"],
  "active": true,
  "address": {
    "city": "Chennai",
    "country": "India"
  }
}

JSON Syntax Rules

Wrap object in {} (curly braces)
Wrap arrays in [] (square brackets)
Keys must be in "double quotes" — single quotes are invalid
Values can be: string (in quotes), number, boolean (true/false), null, object, array
No trailing commas — invalid: {"a":1,}
No comments — JSON doesn't allow // or /* */
UTF-8 encoding

What This Tool Does

✨ Format / Pretty Print

Takes minified or messy JSON and indents it beautifully with line breaks. Use 2-space (default) or 4-space indentation.

🔻 Minify

Removes all whitespace, producing the smallest valid JSON. Useful for APIs to reduce bandwidth.

✅ Validate

Checks if your JSON is syntactically correct. Shows the exact line and error if invalid.

📋 Copy

One-click copy of formatted output to clipboard.

Common JSON Errors

Unexpected token — usually unmatched quote, missing comma, or trailing comma
Unexpected end of input — missing closing brace or bracket
Bad escape — invalid \n, \t sequences in strings
Single quotes — JSON requires double quotes for keys and string values
Comments — // and /* */ are invalid in JSON
Undefined values — JSON has null but not undefined

JSON vs Other Formats

vs XML — JSON is smaller, faster to parse, easier to read. XML is more verbose with attributes and namespaces.
vs YAML — YAML is even more readable but indentation-sensitive (whitespace matters). JSON is stricter.
vs CSV — CSV is for tabular data only. JSON handles nested/hierarchical data.
vs JSON5 — JSON5 is a superset allowing comments and trailing commas, but not standard JSON.

Frequently Asked Questions

What is JSON?

JSON (JavaScript Object Notation) is a lightweight data format used for storing and exchanging structured data. It's human-readable, uses key-value pairs, and is the standard for APIs and config files.

How does JSON validation work?

A JSON validator checks if your text follows JSON syntax rules: matched braces/brackets, quoted strings, valid numbers, proper commas. Invalid JSON gets flagged with the exact line and error message.

Why does my JSON have a "Unexpected token" error?

Common causes: missing comma between properties, extra comma at end (trailing comma — invalid in strict JSON), single quotes instead of double, unquoted keys, or unescaped special characters in strings.

Is my data private when I use this tool?

100% private. All formatting and validation happens in your browser using JavaScript. Your JSON never leaves your device — nothing is sent to any server.

Can I use JSON5 features here?

This tool uses strict standard JSON (ECMA-404). JSON5 features like comments, trailing commas, and unquoted keys are NOT supported and will be flagged as errors.

How do I escape special characters in JSON strings?

Use backslash: \" for quote, \\ for backslash, \n for newline, \t for tab, é for unicode characters.

Input JSON 0 chars

Output 0 chars

What is JSON?

JSON Syntax Rules

What This Tool Does

✨ Format / Pretty Print

🔻 Minify

✅ Validate

📋 Copy

Common JSON Errors

JSON vs Other Formats

Frequently Asked Questions

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