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JSON Validator & Repair

Developer utilities · Done in 3 steps

Stays on your deviceFree · No sign-up
  1. 1Paste your JSON
  2. 2
  3. 3
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About

Validate JSON as you type with the exact line and column of each error, plain-English fix hints and one-click repair of common mistakes.

How to use it

  1. 1Paste the JSON you want to check.
  2. 2Read the error message and the caret pointing at the exact character.
  3. 3Review the likely causes listed underneath.
  4. 4Click Repair JSON to fix trailing commas, quotes, comments and similar issues automatically.
You give
JSON or “almost JSON” (JavaScript objects, Python dicts, JSON with comments)
You get
Valid/invalid verdict, error position, fix hints and a repaired, pretty-printed version
Good to know
Validation follows strict RFC 8259 JSON. Repair handles common syntax slips (trailing commas, single or smart quotes, unquoted keys, comments, True/False/None, missing commas between lines) but cannot guess missing brackets or values.
Privacy
Processed on your device. Nothing is uploaded, stored or logged.
Last tested
2026-10-28

FAQ

Why is a trailing comma an error?

The JSON standard doesn't allow a comma after the last item in an object or array, even though JavaScript does. Many parsers reject it.

Can it convert a JavaScript object or Python dict to JSON?

Often yes. Single quotes, unquoted keys, True/False/None and comments are all converted when you click Repair JSON.

How accurate is the error position?

Exact: the validator walks the text itself rather than relying on browser error messages, which vary and sometimes omit the position.

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