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JSON Formatter, Validator & Beautifier

Format, validate and minify JSON instantly. Catch syntax errors with line-accurate messages.

100% free No sign-up Private · runs in your browser

How to use the free online json formatter & validator

  1. Paste your JSON in the input area.
  2. Result formats and validates automatically.
  3. Errors show line & column numbers.
  4. Copy, or download the formatted file.

About this tool

Pretty-print, minify, validate and fix JSON in seconds. Paste messy JSON, get clean indented output, syntax errors highlighted with line numbers, and a minified version ready for production. For developers debugging APIs or configs, this free online JSON formatter and validator saves minutes every day. Nothing you paste is uploaded — formatting happens locally in your browser.

Key features

Privacy first: every calculation and generation runs 100% locally in your web browser using the Web Crypto API. Your input never touches a server — nothing is stored, logged or sold.

Frequently asked questions

It takes messy minified JSON and adds indentation, newlines and spacing so the structure becomes readable. It can also do the reverse: minify readable JSON to a compact form.
Yes. Strict validation is built in — if your JSON has a syntax error, we report the exact line and column and show a snippet of what went wrong.
No. Formatting and validation happen entirely in your browser. Perfect for pasting sensitive config files.

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