Free · No signup · Runs in your browser

JSON Formatter & Validator

Pretty-print, minify and validate JSON instantly — with the exact line and column of any syntax error.

JSON Formatter & Validator

Pretty-print, minify and validate JSON — with the exact error location.

Runs locally — paste API responses or config safely.

Features

Everything JSON does

A fast, private alternative to online JSON linters — paste API responses and config without sending them anywhere.

Beautify & minify

Switch between neatly indented JSON and a compact single line with one click.

Choose your indent

Format with 2 spaces, 4 spaces or tabs to match your project's style.

Pinpoint errors

Invalid JSON reports the parser message plus the exact line and column so you can fix it fast.

Safe for secrets

Everything is parsed locally, so tokens and private payloads never leave your browser.

How to use

Format JSON in three steps

1

Paste your JSON into the input box.

2

Click Beautify or Minify and pick your indent width.

3

Copy the result — or read the error message to fix invalid JSON.

FAQ

Questions & answers

Everything you might wonder about this tool.

01What does the validator check?
It parses your text with the browser's native JSON engine. If it is valid you get a confirmation; if not, you get the error message with the line and column where parsing failed.
02Can it handle large JSON?
Yes — formatting happens in your browser and comfortably handles large API responses. Very large files depend on your device's memory.
03Is any of my data uploaded to a server?
No. This tool runs entirely in your browser with JavaScript — your input never leaves your device, so it is safe to use with private tokens, config and source code.
04Is it free, and do I need an account?
Yes, it is completely free with no signup, no install and no usage limits. Open the page and it works instantly on desktop or mobile.
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