Pretty-print, minify, and validate JSON with clear error messages.
JSON is the format almost every API, config file, and web app uses to pass structured data around, but it arrives as one long unbroken string more often than not. A response copied from a browser network tab or a log line is technically valid yet completely unreadable. A JSON formatter takes that dense text and lays it out with proper indentation and line breaks, so you can actually see the shape of the data, spot the field you need, and confirm the whole thing is well formed before you rely on it.
Paste your JSON into the input and the tool pretty-prints it instantly, adding consistent indentation for every nested object and array. If you want the opposite, minify collapses everything back into a single compact line with the whitespace stripped out, which is what you want before pasting into code or shrinking a payload. Validation runs the whole time, so a stray comma or an unquoted key gets caught and pointed out rather than failing silently somewhere downstream.
The real value is in the error messages. Raw parsers tend to say something vague, but a good formatter tells you roughly where the problem sits, whether that is a trailing comma after the last item, a missing closing brace, or a value wrapped in single quotes when JSON demands double. Pretty-printing does not change your data in any way. It only rearranges the whitespace, so numbers, strings, and key order all stay exactly as they were.
Reach for this instead of your code editor when you just need a quick look and do not want to save a file, install an extension, or run a linter. It is faster than writing a script for a one-off check, and unlike many online validators it never sends your data anywhere, which matters when the JSON holds tokens or customer records.
Common uses include tidying an API response before you screenshot it for a bug report, minifying a config blob to paste into an environment variable, checking that a webhook payload is valid before you debug the receiving end, and making a hand-edited settings file readable again after it got mangled. Anyone who works with data files a few times a day ends up leaning on a tool like this.
Everything runs locally in your browser. Your JSON is parsed and reformatted on your own device, nothing is uploaded to a server, there is no sign-up, and the tool is free. The only real ceiling is your device's memory, so extremely large files may feel slow, but everyday payloads format in an instant.
The most common culprits are a trailing comma after the last item in an object or array, keys or strings wrapped in single quotes instead of double, or a stray comment, none of which strict JSON allows. The error message points you near the spot so you can find the offending character quickly.
No. Pretty-printing and minifying only add or remove whitespace, so your keys stay in exactly the order you pasted them. If you need keys sorted alphabetically that is a separate operation this tool does not perform by default.
Pretty-print spreads the data across multiple indented lines so a human can read it, while minify strips every space and newline to produce the smallest single-line version. Use pretty-print to inspect data and minify to store or transmit it compactly.
Standard JSON does not allow comments, so a file with // or /* */ notes will be flagged as invalid. If you are working with JSON5 or JSONC you will need to strip the comments first, since this tool follows the strict specification.
It points out where a problem is but does not guess at repairs, because auto-fixing could silently change your intended data. You make the correction yourself, which keeps the result trustworthy.
There is no fixed cap. Processing happens in your browser, so the practical limit is how much your device's memory can comfortably hold, and multi-megabyte files may format more slowly than tiny ones.
Polished Pixels. All tools. About. Contact. Every tool runs in your browser and your files are never uploaded.