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Paste JSON to validate it, pretty-print with custom indentation, minify it, or explore it in a collapsible tree view — with exact line-and-column error pinpointing.

JSON Formatter and Validator Online – Free Tool

JSON Formatter and Validator

Paste your JSON to validate it, pretty-print it, or minify it — free and instant. Everything runs in your browser; nothing is uploaded.

Input JSON

Indent:

Result

Your formatted JSON will appear here.

Tips

  • Validate first: the Validate button checks your JSON and shows the exact line and column of any error.
  • Tree view: click any object or array to collapse and expand it — handy for large API responses.
  • Minify shrinks JSON for pasting into code or URLs; Format makes it human-readable again.
  • Common errors: trailing commas, single quotes instead of double quotes, and unquoted keys — all flagged below.
100% client-side — your JSON never leaves this page.
100% private

Runs entirely in your browser. Your code is never uploaded to any server.

No signup

Use it instantly. No accounts, no email, no waiting.

Free forever

No trial limits, no locked features.

How to use the JSON Formatter & Validator

  1. Paste your JSON

    Drop your JSON into the input box, or click Sample to try the tool with example data first.

  2. Format, minify, or validate

    Click Format for a readable layout, Minify to compress it for code or URLs, or Validate to check the syntax.

  3. Fix any errors

    If the JSON is invalid, you get the exact line and column of the problem, plus notes on common mistakes like trailing commas or single quotes.

  4. Explore and copy

    Switch to Tree view to collapse and expand large objects and arrays, then hit Copy output to grab the result.

Features

One-click formatting

Turn messy, single-line JSON into clean, indented output instantly.

Minify for production

Strip whitespace and shrink JSON for pasting into code, configs, or URLs.

Precise validation

Get the exact line and column of every syntax error instead of a vague error message.

Interactive tree view

Click any object or array to collapse and expand it, which is handy for large API responses.

Sample data built in

Test the tool immediately with one click, no need to find JSON of your own.

100% client-side

All parsing happens in your browser, so your code and API data never leave this page.

Frequently asked questions

Is the JSON Formatter really free?
Yes. Free with no signup, no usage limits, and no locked features.
What does the Validate button do?
It checks your JSON syntax and reports exactly where each error is, with the line and column number, so you can fix it fast.
What is the difference between Format and Minify?
Format adds indentation and line breaks so humans can read the structure. Minify removes all unnecessary whitespace so the JSON is as small as possible for code, configs, and URLs.
What is Tree view for?
Tree view turns your JSON into an interactive explorer. Click any object or array to collapse or expand it, which makes large API responses much easier to navigate than raw text.
What common errors does it catch?
Trailing commas, single quotes instead of double quotes, unquoted keys, and missing brackets or braces, all flagged with their exact location.
Is my JSON uploaded anywhere?
No. Formatting, validation, and minification all happen locally in your browser, so your code stays completely private.

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