JSON Formatter & Validator

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Paste any JSON to pretty-print it with your choice of indentation, minify it to a single compact line, or validate it instantly. Invalid JSON is flagged with a clear message and the exact line and column of the problem, so you can fix it fast. Free, fast, and runs entirely in your browser — your data never leaves your device.

Input
Output
Formatted output appears here.

How to use

Paste or type JSON into the input box. Choose an indent width, then click Pretty-print to format it or Minify to collapse it to one line. Valid JSON shows formatted output you can copy; invalid JSON shows the error with its line and column.

Frequently asked questions

Is the JSON formatter free?
Yes. It's completely free, needs no sign-up, and runs entirely in your browser.
Does my JSON get uploaded anywhere?
No. All parsing and formatting happens locally in your browser — your data never leaves your device.
What happens when my JSON is invalid?
The tool reports that the JSON is invalid and points to the exact line and column where parsing failed, along with the underlying error message, so you can locate and fix the problem quickly.