JSON Formatter

How it works

1. Paste your JSON into the input box. An API response, a config file, a log line, anything that should be valid JSON.
2. Pick Format to pretty-print it or Minify to strip all whitespace into a single line. Choose the indentation your project uses: 2 spaces, 4 spaces or tabs.
3. Turn on Sort keys if you want object keys in alphabetical order, which makes diffs and code reviews much easier to read.
4. Press Format JSON. If the input is invalid, the error message tells you the line and column of the problem so you can fix it immediately.

Frequently asked questions

Is my JSON sent to a server?

No. Parsing and formatting run with the browser's built-in JSON engine on your own device. You can paste API responses containing tokens, customer data or internal configuration without anything leaving the page.

What does the formatter check for?

It checks strict JSON syntax as defined by RFC 8259: double-quoted keys, no trailing commas, no comments, no single quotes, no unquoted keys. If your text is JavaScript object notation or JSON5, it will be flagged as invalid at the first offending character.

Does sorting keys change the meaning of my data?

Not for objects. JSON objects are unordered by definition, so consumers must not rely on key order. Arrays are never reordered because their order is meaningful. Sorting is applied recursively to every nested object.

Why do large numbers or Unicode strings look different after formatting?

JSON numbers are parsed as JavaScript doubles, so integers above 2^53 (about 9 quadrillion) lose precision and very long decimals are rounded. Escaped Unicode sequences like \u00e9 are shown as the actual character. If you need exact big integers, keep them as strings.

What is the difference between format and minify?

Format adds line breaks and indentation so humans can read the structure. Minify removes every optional whitespace character, producing the smallest valid JSON for embedding in URLs, environment variables or network payloads. Both produce semantically identical data.