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JSON Formatter & Validator

🔒 In your browser

Pretty-print, minify and validate JSON with exact error line & column.

✓ Valid JSON

Output
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±You might also need JSON Diff / Compare →

About the JSON Formatter & Validator

JSON (JavaScript Object Notation) is the most common format for APIs and config files, but minified or hand-edited JSON is hard to read and easy to break. This free JSON formatter and validator pretty-prints JSON with clean indentation, minifies it back to one line, and validates it — pointing to the exact line and column of any syntax error.

Everything runs in your browser, so even large or sensitive payloads are never uploaded to a server.

How to format and validate JSON

  • Paste or type your JSON into the input.
  • It's validated live — errors show the exact line and column so you can fix them fast.
  • Use Beautify to indent and Minify to strip whitespace for production.
  • Copy the result with one click.

Common JSON errors it catches

  • Trailing commas after the last item in an object or array.
  • Single quotes instead of double quotes around keys and strings.
  • Missing commas, brackets or braces.
  • Unquoted keys and stray comments (not valid in strict JSON).

Frequently asked questions

What does a JSON formatter do?

It reformats JSON so it's readable — adding consistent indentation and line breaks (beautify) — or compresses it to a single line (minify), while validating that the syntax is correct.

How do I find the error in invalid JSON?

Paste it here and the validator reports the exact line and column of the first syntax error, along with what's wrong, so you can jump straight to it.

Is my JSON sent to a server?

No. Formatting and validation happen entirely in your browser with JavaScript, so your data is never uploaded — safe for sensitive API responses.

What's the difference between beautify and minify?

Beautify expands JSON with indentation for humans to read; minify removes all unnecessary whitespace to make the payload as small as possible for transfer.

Related searches

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Learn more

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🔗 Embed this tool on your website — free

Copy this and paste it into your page's HTML. The tool runs in the visitor's browser, just like here. Change height to fit, or add the optional auto-resize snippet below. Add ?theme=dark to the URL for dark mode.

<iframe src="https://toolhq.dev/embed/json-formatter/" title="JSON Formatter & Validator — ToolsHub" width="100%" height="520" style="border:1px solid #e5e7eb;border-radius:12px;max-width:680px" loading="lazy"></iframe>
Optional: auto-resize the iframe height

Add this once on the same page so the iframe grows to fit the tool:

<script>
addEventListener("message", function (e) {
  if (e.data && e.data.type === "toolshub:resize") {
    document.querySelectorAll('iframe[src*="/embed/"]').forEach(function (f) {
      if (f.contentWindow === e.source) f.style.height = e.data.height + "px";
    });
  }
});
</script>