How to Format & Pretty-Print JSON: Tools & Code Techniques

Why Format JSON?

Raw API responses and log streams are typically compressed into dense single-line strings. Formatting adds indentation and line breaks, turning unreadable payloads into structured, reviewable code.

Programmatic Pretty-Printing

JavaScript (Node.js & Browser)

Use the third argument of JSON.stringify to specify indentation spacing:

const user = { id: 1, name: "Alice", active: true };

// Format with 2 spaces:
const pretty2 = JSON.stringify(user, null, 2);

// Format with 4 spaces:
const pretty4 = JSON.stringify(user, null, 4);

// Format with tabs:
const prettyTab = JSON.stringify(user, null, "\t");

Python

Pass the indent parameter to json.dumps():

import json

payload = {"status": "ok", "count": 42}
formatted = json.dumps(payload, indent=2)
print(formatted)

Command Line (jq)

# Pretty print a file
cat payload.json | jq .

# Pretty print API curl response
curl -s https://api.example.com/data | jq .