How to Format JSON in Python

Basic JSON Formatting with json.dumps

Python's built-in json module provides everything you need to format JSON. The indent parameter is the key — it controls how many spaces (or a string like "\t") are used per indentation level.

import json

data = {"name": "Alice", "age": 30, "city": "Paris"}

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

# 4-space indentation
print(json.dumps(data, indent=4))

# Tab indentation
print(json.dumps(data, indent="\t"))

Format a JSON String (parse then format)

import json

json_string = '{"name":"Alice","age":30,"city":"Paris"}'

# Parse then format
data = json.loads(json_string)
formatted = json.dumps(data, indent=2)
print(formatted)

Sort Keys Alphabetically

import json

data = {"zebra": 1, "apple": 2, "mango": 3}
print(json.dumps(data, indent=2, sort_keys=True))
# Output:
# {
#   "apple": 2,
#   "mango": 3,
#   "zebra": 1
# }

Format a JSON File

import json

# Read and reformat a JSON file
with open('data.json', 'r') as f:
    data = json.load(f)

with open('data_formatted.json', 'w') as f:
    json.dump(data, f, indent=2, ensure_ascii=False)

Format JSON from the Command Line (Python one-liner)

# Pipe JSON to Python's json.tool module
echo '{"name":"Alice","age":30}' | python3 -m json.tool

# Format a file
python3 -m json.tool data.json

Handle Non-ASCII Characters (Unicode)

import json

data = {"city": "São Paulo", "greeting": "Olá"}

# By default, json.dumps escapes non-ASCII as \uXXXX
# Use ensure_ascii=False to keep Unicode characters readable
print(json.dumps(data, indent=2, ensure_ascii=False))
# Output:
# {
#   "city": "São Paulo",
#   "greeting": "Olá"
# }

Need to format JSON without writing code?

Paste any JSON into the free online formatter — instant results, no Python environment needed.

Frequently Asked Questions