JSON Formatter & Validator - Format, Minify, Validate JSON Online

Paste your JSON to instantly format it with proper indentation, validate it with clear error messages pointing to the exact line, or minify it for production use. Everything runs in your browser — no data is sent anywhere.

Features

Format

Pretty-print JSON with 2-space indentation for easy reading and editing.

Minify

Compress JSON by removing all whitespace for smaller payload sizes.

Validate

Check if your JSON is valid with clear error messages showing exactly where the problem is.

Common JSON errors this tool catches

  • Trailing commas{"a": 1,} is invalid JSON
  • Single quotes — JSON requires double quotes: {'key': 'value'} is invalid
  • Missing commas — Between key-value pairs or array elements
  • Unquoted keys{key: "value"} is JavaScript, not JSON
  • Comments — JSON does not support // comments or /* blocks */