Developer tools
JSON Formatter / Validator
Paste JSON and get instant formatting with line-accurate error reports
🔒 All data is processed in your browser. Nothing is uploaded to any server.
Quick guide
What can JSON Formatter help you do?
Free online JSON formatter, minifier, and validator. Error line-number locator, tree view, one-click copy. Runs in browser — your JSON never uploaded.
Best for
JSON Formatter helps with quick debugging, API data cleanup, format checks, and small code or config tasks without opening an IDE or installing a package.
How to use it
For JSON Formatter, paste the text, code, or configuration into the input area, choose the mode you need, and run it. For large data, test a small sample first.
How to read the result
After using JSON Formatter, the output is kept copy-friendly for docs, code, and config files. When validation is available, fix the reported error location before trusting the final output.
Privacy and limits
When using JSON Formatter, most processing happens in the browser. Do not paste passwords, private keys, tokens, or unmasked production data into any online tool.
For JSON Formatter: Developer tools are for quick inspection and conversion. They do not replace tests, linting, security review, or version control.
Frequently Asked Questions
How do I find a JSON syntax error?
This tool reports the exact line and position, like "Unexpected token at line 5, position 12", and highlights the line.
Can I minify JSON?
Yes — the "Minify" button compresses multi-line JSON to one line for API payloads or database storage.
Is there a one-click copy?
Yes — the copy button at the top-right of the output box copies the formatted JSON to your clipboard.
Does this tool store my JSON?
No. All processing happens in your browser. Your JSON is never uploaded — safe for sensitive data.
What's the max JSON size?
Theoretically unlimited (browser memory permitting). 10 MB or less is fast in testing.