JSON Validator
Validate JSON syntax and show errors.
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Tool guide
JSON Validator: how it works
Practical information to understand the result and use this tool correctly.
About JSON Validator
A JSON validator parses your document with strict rules: double-quoted keys and strings, no trailing commas, and valid structure.
Use it when an API rejects a body, a config file fails to load, or a minified blob looks suspicious. Feedback should point to where parsing stopped.
Validation runs locally—paste only data you are comfortable handling on your device.
How to use it
- 1Paste the JSON to check.
- 2Run validation.
- 3Fix reported syntax issues and re-check.
Frequently asked questions
- Why are trailing commas invalid?
- Standard JSON does not allow a comma after the last item in an object or array. Some languages allow it; JSON parsers usually do not.
- Single quotes?
- JSON requires double quotes for strings and keys. Single quotes will fail validation.