JSON Validator
Check whether JSON is valid and see exactly where it breaks.
Everything is processed in your browser. Nothing you paste is uploaded or stored.
About these formats
A validator answers one question: will a parser accept this? When the answer is no, the useful part is the position — this tool reports the line and column of the first syntax error rather than only saying the document is invalid.
How to use this tool
- Paste the JSON you want to check.
- The result appears immediately: either confirmation that it is valid, or the error with its line and column.
- Fix the reported position and the message updates as you type.
Frequently asked questions
Is my JSON sent to a server?
No. Everything happens in your browser. Nothing you paste is uploaded, logged or stored, which matters when the document contains keys, tokens or personal data.
Why is my JSON reported as invalid?
The most common causes are trailing commas, single quotes instead of double quotes around keys and strings, and unescaped line breaks inside a string. The error message gives the line and column of the first problem.
Does it change my data?
No. The document is parsed and re-serialised, so only whitespace changes. Key order is preserved and values are untouched.
Can it handle large documents?
Yes, within your browser's memory. Documents of a few megabytes are fine; extremely large files may make the page pause briefly while it parses.