JSON Formatter
Format, validate and beautify JSON instantly.
Runs in your browser — your text never leaves your device.
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About this tool
A JSON formatter takes machine-generated JSON — usually delivered as one unreadable line — and rewrites it with consistent indentation so you can actually read it. This one validates as it formats: if the JSON is malformed, you get the reason and the exact line and column instead of a vague failure. You can choose two or four spaces or tabs to match your project's style, sort object keys alphabetically to make two payloads easy to compare, and minify in the other direction when you need the smallest possible output. Everything happens locally in your browser, which means API responses, config files and anything else you paste are never uploaded, logged, or seen by us. That matters when the JSON you are debugging contains tokens, customer records, or anything else you would not paste into a stranger's server.
How to use it
- Paste your JSON into the box
- Pick your indentation, and sort keys if you want them alphabetical
- Click Format, then copy or download the result
Frequently asked questions
Is my JSON uploaded anywhere?
No. The formatter runs entirely in your browser using the built-in JSON parser. Nothing you paste is sent over the network, so it is safe to use with API responses that contain tokens or personal data.
Why does it say my JSON is invalid?
The most common causes are trailing commas after the last item, single quotes instead of double quotes, unquoted keys, and comments — none of which are legal JSON. The error message shows the line and column so you can jump straight to the problem.
What is the difference between formatting and minifying?
Formatting adds whitespace and line breaks so a human can read the structure. Minifying strips all of it to produce the smallest valid output, which is what you want when sending JSON over the network or embedding it in a file.
Does sorting keys change my data?
No. Key order carries no meaning in JSON objects, so sorting produces an equivalent document. It is useful when you want to diff two responses that list the same keys in a different order.
Is there a size limit?
The practical limit is your device's memory rather than a fixed cap. Files of a few megabytes format without trouble on a typical laptop or phone.