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Click Format to see output here...How to use
01
Paste your JSON
Drop the raw payload into the Input box, or press Try sample to load an example. Minified, mangled, or copied straight from DevTools all work fine.
02
Pick an indent and press Format
Choose 2 or 4 spaces with the Indent selector, then click Format. The tool parses the input and reprints it; invalid input shows the exact parse error instead.
03
Copy the result
Hit the Copy button next to the Formatted output pane. The footer shows character and line counts, which helps when you're keeping an eye on payload size.
Why JSON Formatter
- Runs entirely in your browser, your data never leaves your device.
- Catches parse errors with the exact problem location.
- Adjustable 2-space, 4-space, or tab indentation.
- No file size limit beyond your browser memory.
Common questions
What happens to my JSON when I click Format?
The tool parses your input into a real data structure, then prints it back out with the indent you selected. Values, key order, and types are untouched; only whitespace changes. That's why the output always parses identically to the input.
Does formatting also catch errors in my JSON?
Yes, because nothing can be formatted until it parses. In practice that makes this a json formatter and validator in one pass, and a handy json format checker before you ship a config. It won't rewrite broken input for you though, so treat it as a checker rather than a json corrector: you fix the reported position yourself.
Can I beautify JSON that arrives on a single line?
That's the main use case. Paste the one-liner and the json beautify pass expands every object and array onto its own lines. Some people call the result json beauty or pretty printing; either way the data stays identical and only becomes readable. It's the same job people mean when they search for a json beautifier online.
Why won't my JSON format?
Almost always a syntax problem: a trailing comma after the last item, single quotes instead of double quotes, comments, or an unquoted key. The error message includes the position where parsing stopped, so start there. The parser is strict on purpose, since lenient parsing would hide bugs your production code will hit later.
Is this the best json formatter for very large payloads?
There's no artificial size cap; the only limit is your browser's memory, and multi-megabyte payloads format fine on a normal laptop. The character and line counts under the output help you confirm nothing was truncated. For anything that chokes a browser tab, a command line tool is the better fit.
Is building new JSON from scratch possible here?
It's not a json creator or a json form with fields to fill in; there's no builder UI. That said, plenty of people write JSON by hand in the input box and press Format repeatedly as a live syntax check, which gets you most of the way there.
Do I need to install an extension to use it?
No. The page is the tool: open it, paste, format. Nothing is uploaded either, since parsing happens locally with your browser's own JSON engine, so it's safe for tokens, credentials, and customer data you'd rather not paste into random sites.
What do the character and line counts under the output mean?
After formatting, the footer reports the exact size of the result and how many lines it spans. It's a quick way to gauge how much larger indented output is compared to the minified version, and to spot suspiciously short output that suggests you pasted a fragment.