JSON Validator
Validate JSON and get a precise error message with the line and position when something is wrong, plus a summary of your data.
- Free
- No sign-up
- Runs in your browser
Your data is validated locally in your browser and never uploaded.
How to use JSON Validator
- Paste the JSON you want to check.
- The result appears instantly — valid, or an error with the position.
- For valid JSON, view a summary of its structure.
About this tool
A single misplaced comma can break an entire integration. The validator checks your JSON against the official grammar and reports exactly what is wrong and where, so you can fix it in seconds.
When to use it: the moment a config or payload “should work but doesn’t” — find the exact syntax error.
Frequently asked questions
What counts as valid JSON?
Double-quoted keys, no trailing commas, no comments, and only the supported value types: string, number, boolean, null, object and array.
Does the validator tell me where the error is?
Yes. When possible it reports the line and column, which is usually enough to spot the problem immediately.
What is the difference between the validator and the formatter?
The validator only checks and reports — perfect when you need a quick yes/no. The formatter additionally rewrites indentation.
Are comments or JSON5 supported?
No — only strict standard JSON. Comments, trailing commas and single quotes are reported as errors, which is usually exactly what you need to find.
Why does a number like 007 fail?
Leading zeros are not allowed in JSON numbers. Write 7 (or "007" as a string, if the zeros matter).
Is my data sent anywhere while validating?
No — validation is a local check in your browser, safe for configuration files and payloads.
Related tools
How to use Json Validator
Paste your code, data, or URL into the Json Validator input area. Select the appropriate mode or option, then process. The formatted or converted output appears clearly and can be copied or saved.
Practical benefits
- Complete tasks faster without installing additional software.
- Keep files private since processing happens in your browser.
- Produce consistent results that integrate into your workflow.
Frequently asked questions
Is this tool free to use?
Yes. Json Validator is fully free with no account or subscription required.
Does it upload my files?
No. All processing occurs locally within your browser session.
Can I use this for professional projects?
Yes, the tool is designed for both casual and professional use. Always verify critical outputs.