How to Pretty Print JSON – Browser, JavaScript, Python, curl

Pretty printing JSON adds indentation and line breaks to compact JSON to make it human-readable — the data is identical, only whitespace changes. In JavaScript: JSON.stringify(data, null, 2). In Python: json.dumps(data, indent=2). In the terminal: cat file.json | python -m json.tool. Or paste directly into the JSON Formatter for instant formatting in your browser.

In the browser — the fastest option for one-off inspection

If you have a JSON blob from an API response or a log file and need to read it right now, paste it into the JSON Formatter. It formats the JSON instantly with a collapsible tree view and 2-space indentation. No setup, no install — works entirely in your browser.

In JavaScript — JSON.stringify with the space parameter

JSON.stringify(value, replacer, space) — the third argument controls indentation:

const data = {
    name: "Alice",
    age: 28,
    roles: ["admin", "editor"],
    address: { city: "London", country: "UK" }
};

// 2-space indent (most common)
console.log(JSON.stringify(data, null, 2));

// 4-space indent
console.log(JSON.stringify(data, null, 4));

// Tab indent
console.log(JSON.stringify(data, null, '\t'));

Pass null as the second argument to include all keys. See the full guide on JSON.stringify indent options for more on the replacer parameter.

In Python — json.dumps with indent

import json

data = {"name": "Alice", "age": 28, "roles": ["admin", "editor"]}

# 2-space indent
print(json.dumps(data, indent=2))

# Sorted keys + 2-space indent
print(json.dumps(data, indent=2, sort_keys=True))

For more Python-specific options including file reformatting, see How to Format JSON in Python.

In curl — pipe to python -m json.tool or jq

The quickest way to pretty-print an API response directly in your terminal:

# Using Python's built-in json.tool (no extra install required)
curl -s https://api.example.com/users | python -m json.tool

# Using jq (if installed — more powerful, colorised output)
curl -s https://api.example.com/users | jq '.'

# Format and save to file
curl -s https://api.example.com/users | python -m json.tool > users-formatted.json

In Node.js

const https = require('https');

https.get('https://api.example.com/data', (res) => {
    let body = '';
    res.on('data', chunk => body += chunk);
    res.on('end', () => {
        const data = JSON.parse(body);
        // Pretty-print to console
        console.log(JSON.stringify(data, null, 2));
    });
});

In VS Code

Open a .json file and press Shift+Alt+F (Windows/Linux) or Shift+Option+F (Mac) to format the document using VS Code's built-in JSON formatter. This respects your editor's indentation settings.

When to pretty-print vs when to minify

Pretty print during development, debugging, and code review — it makes structures clear at a glance. Minify for production payloads where bandwidth matters. Use the JSON Minifier to strip all whitespace before shipping JSON over the network.

Pretty-printing large or streamed JSON

For very large files, loading the whole document into memory just to reformat it can be slow or impossible. Command-line jq is the best tool here because it streams: jq '.' big.json formats a multi-megabyte file without holding a formatted copy of the entire thing in an editor. If the data is newline-delimited JSON (NDJSON / JSON Lines), don't try to format it as one document — each line is its own JSON value. Format them individually with jq -c '.' data.ndjson to keep one object per line, or jq '.' data.ndjson to expand each. For an occasional large blob you just need to read once, the browser-based JSON Viewer renders it as a collapsible tree so you can drill into the branch you care about instead of scrolling thousands of formatted lines.

Common pretty-printing pitfalls

A few surprises catch people out. First, non-ASCII characters: Python's json.dumps escapes them to \uXXXX by default, so an accented name or emoji looks mangled — pass ensure_ascii=False to keep the real characters. Second, key order: most formatters preserve insertion order, but adding sort_keys=True (Python) or piping through jq -S gives you alphabetical keys, which makes two JSON files diff cleanly. Third, trailing output: console.log and print add a newline, which is usually fine, but if you're writing to a file that another tool parses strictly, make sure you're not adding a stray blank line. Finally, remember that pretty-printing is purely cosmetic — a formatted and a minified version of the same data parse to identical objects, so never rely on whitespace to carry meaning.