JSON tools
JSON Validator & Syntax Checker
Check whether your JSON is valid and pinpoint the exact line and reason when it is not, with clear, plain-English error messages.
How to use it
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Paste your JSON
Paste your JSON into the editor or drop a .json file onto the page.
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Validate it
Click Validate to parse the JSON and surface the first error with its line and a plain-English explanation.
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Fix and re-check
Correct the highlighted issue and validate again until you get a clean, valid result.
Frequently asked questions
Is the JSON validator free?
Yes, free to use as often as you like, with no account and no limits.
Is my JSON uploaded to validate it?
No. Validation runs entirely in your browser. Nothing is sent to a server, so confidential JSON never leaves your machine.
What does the validator check?
It parses your input against the JSON standard (RFC 8259) and reports the first syntax error with its location, catching trailing commas, missing or extra brackets, unquoted keys, single quotes, and invalid escape sequences.
What are the most common JSON errors?
By far the most common are a trailing comma after the last item, using single quotes instead of double quotes, unquoted keys, and comments (which standard JSON does not allow). The error message points you at the exact spot.
Is there a file size limit?
No fixed limit. Validation runs locally, so the only constraint is your device’s memory. Large files are handled comfortably.
My JSON is valid. How do I format or host it?
Once it validates, use the JSON Beautifier to pretty-print it, or the JSON Minifier to compress it, and from either you can publish the file to a live HTTPS link.