100% private · runs in your browser

JSON Validator & Formatter

Paste JSON to check it, pretty-print it, or compress it, and find syntax errors fast.

✓ Free forever✓ No sign-up✓ No watermark✓ Files never leave your device

How to use the JSON Validator & Formatter

  1. Paste your JSON into the box.
  2. Click Validate & format, or Minify to compress it.
  3. Fix any error shown, then copy the result.

Invalid JSON is reported with the line and column where parsing failed. Common causes are trailing commas, single quotes instead of double quotes, and unquoted keys. Valid JSON is re-indented using the spacing you choose.

Why use Toolbox

Private by designProcessing happens on your device. Nothing is uploaded to a server.
FastNo waiting for uploads or queues. Results appear instantly.
Works everywhereUse it on phone, tablet or desktop in any modern browser.
Truly freeNo account, no watermark and no hidden paywall.

Frequently asked questions

What makes JSON invalid?

The usual causes are trailing commas, single quotes, unquoted property names, comments, and missing brackets or quotes.

What is the difference between format and minify?

Formatting adds indentation so people can read it. Minifying removes all extra whitespace to make the file smaller.

Is this tool really free?

Yes, always free with no sign-up, no watermark and no file limits set by us.

Are my files uploaded anywhere?

No. Everything happens inside your browser, so your files and text never leave your device.

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About JSON Validator & Formatter

Validate JSON syntax, format nested objects for readability, or minify JSON for compact output. This is useful when checking API payloads, configuration, and structured data.

How to use JSON Validator & Formatter

  1. Paste JSON into the editor.
  2. Choose validate, format, or minify.
  3. Fix any reported syntax errors and copy the corrected output.

Frequently asked questions

What makes JSON invalid?

Common causes include trailing commas, single-quoted strings, missing quotes around property names, and unmatched brackets.

Does formatting change the data?

Formatting changes whitespace and layout, not the parsed values, when the input is valid JSON.

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