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JSONDiff.in

JSON Validator

Find syntax errors with exact line and column

JSON input

Validation runs as you type

Waiting for input

Paste or upload JSON. Results update automatically.

How to use

  1. Paste or upload your JSON. Validation runs automatically as you type.
  2. If there is a syntax error, read the explanation, click Go to error to jump to it, or click Repair to fix it automatically.
  3. Valid documents show structure statistics and any duplicate keys.
  4. Use Format to pretty-print the document once it is valid.

Common JSON errors this validator catches

  • Missing comma between properties or array items.
  • Trailing comma after the last property or item.
  • Single quotes or unquoted property names (JavaScript object syntax is not JSON).
  • Comments, which JSON does not allow.
  • Literals such as undefined, NaN, True or None that come from other languages.
  • Unterminated strings and unbalanced brackets or braces.
  • Duplicate keys, reported as warnings.

Frequently asked questions

The text follows the JSON specification (RFC 8259): double-quoted keys and strings, no trailing commas, no comments, and exactly one top-level value. If JSON.parse would accept it, it is valid.