JSON Formatter & Validator

Pretty-print, minify, and validate JSON. Errors are highlighted with exact line and column. Runs entirely in your browser.

Output 
Output appears here.
What is JSON?

JSON in 30 seconds

JSON (JavaScript Object Notation) is the most common way computers exchange structured data on the web. It's plain text, human-readable, and supported by every programming language.

The whole syntax

  • { } — an object (key/value pairs)
  • [ ] — an array (ordered list)
  • "text" — a string (always double-quoted)
  • 42 or 3.14 — a number
  • true / false — a boolean
  • null — explicit absence of a value

Common mistakes

  • Trailing commas: [1, 2, 3,] is invalid JSON (though JavaScript allows it).
  • Single quotes: {'name': 'Ada'} is invalid; strings must use double quotes.
  • Unquoted keys: {name: "Ada"} is invalid; keys must be quoted strings.
  • Comments: JSON has no comments. If you see // or /* */, it's JSON5 or JSONC, not strict JSON.