Tool 04 / Developer & SEO
JSON Formatter
Paste raw JSON to pretty-print it, minify it for production, or find out exactly why it fails to parse. Nothing is uploaded — validation uses your browser's JSON parser.
Validation runs with the browser's native JSON parser.
Nothing formatted yet
Paste JSON and press Format to pretty-print it, or Minify to strip whitespace for production.
Manual
04 stepsHow to use it
- 01Paste raw JSON, or press Load sample to see an example.
- 02Choose an indentation size and press Format to pretty-print.
- 03Press Minify if you need a compact payload for production.
- 04Copy or download the result; the error panel explains invalid input.
Example
What it looks like
- Input
- { "plan": "pro", "seats": 4, }
- Output
- Unexpected token } … check for a trailing comma after "seats": 4
JavaScript object literals allow trailing commas; JSON does not.
Method
How it works
Formatting parses the text with JSON.parse, then re-serialises it with the indentation you chose. If parsing fails, the tool shows the parser message and the position where it gave up.
Minifying removes insignificant whitespace between tokens. It does not rename keys, change number precision, or reorder arrays, so the data means exactly the same thing.
A valid document must start with an object, array, string, number, boolean or null. Single quotes, comments, NaN and trailing commas are not JSON — many pasted errors come from those four shortcuts.
FAQ
Before you ask
Specific to json formatter, including limits and privacy.
Is my JSON uploaded anywhere?
No. Formatting and validation use your browser's native JSON parser, so the content stays on your device.
Can I sort keys alphabetically?
Not currently. Key order is preserved to avoid changing arrays or dependent code. The roadmap includes an optional sort toggle that leaves arrays untouched.
Does formatting fix invalid JSON?
No tool can reliably guess intent. The error message points to the failing position so you can fix quotes, commas or brackets manually.
Is there a size limit?
The editor handles a few megabytes comfortably. For very large files, use a command-line formatter such as jq.
Privacy
Your JSON is processed in your browser and never transmitted to us.
Read the privacy policy for data retention, analytics and contact details.
Limits
Results depend on the input you provide and your browser. Always sanity-check important numbers before publishing or billing.
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