MMaxTools

JSON Validator

Check if your JSON is valid and find syntax errors with exact line and column.

The JSON Validator checks whether a payload is syntactically correct JSON — and when it is not, it tells you exactly why and where. Paste your data and the validator responds instantly: a green 'Valid JSON' confirmation, or a precise error naming the problem at its line and column.

Most 'invalid JSON' moments are small mistakes: a missing comma between properties, a stray trailing comma after the last item, single quotes instead of double quotes, or an extra closing brace. Knowing the exact position turns a frustrating hunt into a ten-second fix.

Validation runs locally in your browser with the standard JavaScript parser, so nothing you paste is uploaded. The same engine powers the Format and Minify buttons on the JSON Formatter page when you are ready to clean the output.

How to use the JSON Validator

  1. Paste your JSON into the text area.
  2. Watch the status line: it confirms valid JSON or flags an error immediately.
  3. Read the error message with its line and column.
  4. Fix the reported position and watch the status turn green.
  5. Copy or reuse the corrected JSON elsewhere.

Frequently asked questions

What makes JSON invalid?

Common causes: missing commas between properties, trailing commas, single quotes instead of double quotes, unquoted keys, mismatched braces or brackets, and non-string values written bare. The validator pinpoints the first offending position.

Does 'valid JSON' mean the data is correct?

No — validation only confirms syntax. A payload can be perfectly valid JSON yet wrong for your API (missing required fields, wrong types). This tool checks grammar; semantic checks belong to your schema.

Is my data sent anywhere?

No. Parsing happens entirely in your browser using JavaScript's built-in JSON parser. You can safely validate production configs and internal payloads.

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