JSON Prettifier Tool

Format, validate, and minify JSON live as you type, with the exact parser error if it's invalid.

Runs in your browser, nothing sent

json-prettifieryour input stays here

Indent

JSON input

{"name":"Bytelify","tools":210,"active":true}

Formatted

{
  "name": "Bytelify",
  "tools": 210,
  "active": true
}

Formatted live as you type, entirely in your browser. Invalid JSON shows the parser's exact error message so you can find the problem quickly.

Need the opposite? JSON Minify Tool

What is JSON Prettifier Tool?

Paste minified or messy JSON and this JSON beautifier (also called a JSON prettifier or formatter) indents it properly instantly, choose 2 spaces, 4 spaces, or tabs. If the JSON is invalid, you get the exact parser error message (what's wrong and roughly where) instead of a generic "invalid JSON" message, so you can fix it faster. A minify button is also included for the opposite direction: squeeze formatted JSON down to a single compact line. Everything happens in your browser; nothing you paste is sent anywhere.

How to Use the JSON Prettifier

1
Paste the JSON: Enter minified or messy JSON.
2
Choose Your Indent: Pick 2 spaces, 4 spaces, or tabs.
3
Read the Formatted Result Instantly: The indented, validated output appears automatically as you type.
4
Copy or Minify: Copy the result, or use the minify button to go the other direction.

How It Works

Your input is parsed with JSON.parse(), which is also what makes this a validator, not just a formatter, then re-serialized with JSON.stringify() using your chosen indent (2 spaces, 4 spaces, or a tab). Every nested object and array is expanded onto its own indented lines based on how deep it sits in the structure. If JSON.parse() throws, formatting stops there and you see its actual error message rather than a generic failure, since the parser already knows exactly where it got stuck.

Example

Before

{"a":1,"b":{"c":2,"d":[1,2,3]}}

After

{
  "a": 1,
  "b": {
    "c": 2,
    "d": [
      1,
      2,
      3
    ]
  }
}

Every nested object and array key expands onto its own line, indented one level deeper than its parent.

Common Use Cases

Making a minified API response readable while debugging, formatting a config file consistently before committing it, or just checking that a JSON blob you're about to paste somewhere is actually valid before you find out the hard way.

FAQs

Frequently Asked Questions

Common questions about JSON Prettifier Tool.

Yes. If the input isn't valid JSON, no formatted output is shown, and you get the JavaScript parser's actual error message so you can locate the problem.

No hard limit set by the tool. Very large JSON (multiple megabytes) may feel slower since parsing happens in your browser's main thread, but typical API responses and config files format instantly.

Yes, use the "Minify input" button, it re-parses your current input and replaces it with the compact, single-line form.

Yes, Bytelify's JSON Prettifier is free with no account or sign-up required.

No. Formatting runs entirely client-side in your browser using JSON.parse()/JSON.stringify(), so nothing you paste is sent anywhere.