JSON Formatter
Format, minify and validate JSON with clear error messages showing exactly where the syntax problem is. Choose 2-space, 4-space or tab indentation and copy
Paste JSON and get it pretty-printed with 2-space, 4-space or tab indentation, minified into one line for transport, or validated with an error message that points at the exact line and column where the syntax breaks. Duplicate keys and trailing commas are the usual culprits, and the error message tells you which one you are looking at.
Formatting is the first thing to do when a JSON API response is unreadable, when a config file has been mangled by an editor, or when a merge conflict has left the braces unbalanced. The tool accepts pasted text and small files, keeps everything in the browser, and never sends your payload anywhere - useful when the JSON contains tokens or customer data.
How to format and validate JSON
Paste your JSON
Choose indentation and format, minify or validate
Copy the result or download it
FAQ
Does it check whether my JSON is valid?
Yes. Invalid input produces the parser message with the position of the problem, which is far quicker than hunting through hundreds of lines by eye.
Which indentation can I choose?
Two spaces, four spaces or a tab, plus a minified single-line output when you want the smallest possible payload.
Is there a size limit?
The tool runs in your browser, so the practical limit is your device memory. Files of a few megabytes format instantly; very large logs may take a moment.
Is my data uploaded?
No. Parsing, formatting and validation all happen locally, which is why it is safe for API responses containing tokens or personal data.
Does it sort or reorder keys?
No, the original key order is preserved, because reordering can change the meaning of a document that depends on field order.
Can it convert JSON to other formats?
Yes - separate tools in this site turn JSON into CSV or XML, and convert CSV or XML back into JSON.
At a glance
| Input | JSON |
|---|---|
| Multiple files | No |
| Where it runs | In your browser - files are never uploaded |
| Works offline | Yes — once the page has loaded |
| Price | Free, no sign-up, no watermark |
Choosing a data format
JSON is the default for anything an API returns or a program reads: it handles nested structures, numbers, booleans and null naturally, and every language parses it. CSV is smaller and opens straight into a spreadsheet, but it has no way to express nesting and no shared standard for the delimiter, quoting or character set - which is exactly where conversions go wrong. XML is verbose but carries attributes, mixed content and schemas, so it still dominates document formats and legacy integrations. YAML is the most readable for configuration but is whitespace-sensitive and has surprising type coercion ("no" becoming false, a version like 1.10 becoming 1.1). Pick the format the consuming tool prefers rather than the one that looks nicest.
Where conversions quietly break
Most conversion bugs are not about syntax, they are about meaning. A CSV column of postcodes loses its leading zeros the moment a spreadsheet guesses it is a number; a long ID exceeds floating-point precision; dates change meaning depending on whether they are day-first or month-first. JSON keys are unordered but arrays are not, and a tool that sorts keys changes nothing while one that sorts arrays changes the data. Unicode is another trap: text can arrive as UTF-8, UTF-16 or with a byte-order mark, and a decoder that guesses wrong turns accented characters into mojibake. Before trusting any conversion, spot-check the first and last row, any field with leading zeros, and any field containing quotes, commas or newlines.