Paste messy JSON here and this json formatter will tidy it into a readable, indented layout in seconds, with no sign-up and nothing to install.
Formatting and validation run in your browser using its built-in JSON parser — nothing is uploaded or stored. If the JSON is invalid, the parser's own error message is shown; where it points depends on your browser.
How to use this tool
Paste your JSON into the box, choose an indent of 2 spaces, 4 spaces or a tab, then press Format/Validate. The tool pretty-prints the result and confirms that it is valid. To format json online in a hurry, the same steps work for a short snippet or a longer document.
What it does
As a json validator, it checks your input with your browser’s own JSON parser, so an error message comes straight from that parser, including its wording and position. As a json beautifier, it rewrites valid JSON with consistent indentation and line breaks, and as a json prettifier it makes nested objects and arrays easy to scan. The Minify button does the opposite: it compresses valid JSON to a single line with no unnecessary spaces, which is handy for pasting into a compact field or URL. When you are happy with the result, copy it with the copy button.
Honest limits
Everything runs in your browser and nothing is uploaded, so your data never leaves your device. That also means the exact error wording and position depend on the browser you are using, and different browsers may describe the same mistake differently. This is a paste-only tool with no file upload, and it cannot repair broken JSON for you: use the minify json tool only after the input validates, and fix any syntax error the parser reports, such as a missing comma or an unclosed bracket.
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Frequently asked questions
No. It reports the error and leaves the fix to you, because an automatic guess could change the meaning of your data. Read the parser message, correct the syntax at the spot it points to, and run the check again.
No. Formatting, validation and minification all happen in your browser. Nothing is uploaded, stored or sent to a server, so you can use the tool with private or sensitive data.
It means the text does not follow JSON syntax, so it cannot be parsed. Common causes are a missing comma, an unclosed bracket or brace, a trailing comma, or a key or string that is not in double quotes. The error message points to where the parser stopped.
It formats JSON into a readable, indented layout, checks whether it is valid, and can also compress it to a single line. You can then copy the result and use it in your own project or document.
A validator only tells you whether the JSON is correct, while a formatter also rewrites it in a tidy, readable layout. This tool does both: it confirms validity and then shows the formatted result.
Choose the style your project or team already uses. Two spaces is compact and common, 4 spaces is easier to scan in deeply nested data, and tabs suit editors set to tab indentation. The choice changes only the layout, not the meaning of the JSON.
Minified JSON takes up less space and is easier to paste into compact fields, URLs or configuration values. It still means exactly the same thing, so you can expand it again later whenever you need to read or edit it.