json Module

Syntax

import json

Examples

import json

data = {
    "name": "Fola",
    "age": 21,
    "skills": ["Python", "TypeScript", "React"]
}

json_string = json.dumps(data)
print(json_string)
# {"name": "Fola", "age": 21, "skills": ["Python", "TypeScript", "React"]}

pretty = json.dumps(data, indent=2)
print(pretty)  # nicely formatted with indentation

import json

json_string = '{"name": "Zain", "age": 22, "active": true}'

data = json.loads(json_string)
print(data["name"])     # Zain
print(type(data))       # <class 'dict'>
print(data["active"])   # True (JSON true becomes Python True)

import json

data = {"project": "DevNexus", "version": "1.0"}

with open("config.json", "w") as f:
    json.dump(data, f, indent=2)

with open("config.json", "r") as f:
    loaded = json.load(f)

print(loaded)

import json

bad_json = "{name: Fola}"  # missing quotes around keys - invalid JSON

try:
    data = json.loads(bad_json)
except json.JSONDecodeError as e:
    print(f"Invalid JSON: {e}")

Best practices

• Use json.dump()/json.load() when working directly with files, and json.dumps()/json.loads() when working with strings already in memory
• Wrap json.loads() in a try/except for json.JSONDecodeError when parsing data from an external or untrusted source
• Use the indent parameter with json.dumps() to produce human-readable output for config files or debugging
• Remember not every Python object is JSON-serializable by default (like datetime or custom classes) - convert them to strings or use a custom encoder first

At a glance

Purpose

Scripting and general-purpose applications

File extension

.py

Runs in

Python interpreter

Usually used with

Python standard library and packages

Specifications & further reading

• Python language reference

Related Python documentation