How to pretty print JSON

Pretty printing (also called beautifying or formatting) turns compact JSON into a readable structure with line breaks and consistent indentation. The data does not change at all; only the whitespace between tokens does. This guide shows what pretty printing does, how to choose an indent style, and how to do it in the browser, on the command line and in code.

Example

APIs usually send JSON minified, on a single line, to save bandwidth:

json
{"user":{"id":42,"name":"Asha","active":true},"roles":["admin","editor"]}

Pretty printed with two-space indentation, the same data becomes easy to scan:

json
{
  "user": {
    "id": 42,
    "name": "Asha",
    "active": true
  },
  "roles": [
    "admin",
    "editor"
  ]
}

Each nested level is indented one step further, every key-value pair gets its own line, and closing braces line up with the line that opened them. That makes it obvious which fields belong to which object.

Pretty print in the browser

1. Open the JSON Formatter and paste your JSON into the left editor, or drop a .json file onto the page.
2. Click Format. The editor re-indents the document and reports an error if the input isn't valid.
3. Switch to tree view to collapse and expand nested objects, or table view if the data is an array of similar objects.
4. Copy the result or download it as a file.

Everything runs locally in your browser, so it's safe to format responses that contain internal data.

Choosing an indent style

• 2 spaces is the most common choice for web APIs and JavaScript projects, and it keeps deeply nested data from drifting off the right edge of the screen.
• 4 spaces is common in Python projects and is slightly easier to scan for shallow documents.
• Tabs let each reader choose their own width but are less common in JSON files.

The best choice is whichever your project already uses. Consistency matters more than the number, because mixed indentation produces noisy diffs.

Pretty print on the command line

If you have jq installed, the identity filter . pretty prints its input:

bash
curl -s https://api.example.com/users/42 | jq .

Python ships with a formatter, so it works on almost any machine:

bash
python3 -m json.tool response.json

Add --indent 2 (Python 3.9+) to change the indent width, or --sort-keys to sort object keys at the same time.

Pretty print in code

JavaScript's JSON.stringify takes an indent argument:

javascript
const pretty = JSON.stringify(data, null, 2);

In Python:

python
import json
pretty = json.dumps(data, indent=2, ensure_ascii=False)

ensure_ascii=False keeps characters such as é or 日本 readable instead of escaping them as é.

Best practices

• Don't pretty print by hand. Hand-editing whitespace is where trailing commas and missing quotes sneak in. Let a formatter do it.
• Format before committing. If JSON files live in a repository, format them consistently so diffs show real changes rather than whitespace.
• Keep key order unless it helps. Formatting doesn't reorder keys. If you also want stable ordering for reviews, see Sort JSON keys.
• Minify for transport, pretty print for people. Servers can send compact JSON, and you can format it when you need to read it. See How to minify JSON.

When formatting fails

If the formatter refuses your input, the JSON is invalid. The most common causes are trailing commas, single quotes and comments. Start with Validate JSON (common errors & fixes).