PythonHow-ToBeginner · 3 min read

How to Send JSON Data in Request Python: Simple Guide

To send JSON data in a request in Python, use the requests library and pass your data as a dictionary to the json parameter in requests.post() or requests.put(). This automatically converts the dictionary to JSON and sets the correct headers.

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Syntax

Use the requests.post() or requests.put() function with the json parameter to send JSON data. The json parameter takes a Python dictionary, converts it to JSON, and sets the Content-Type header to application/json.

Example syntax:

requests.post(url, json=data_dict)
requests.put(url, json=data_dict)

python

import requests

url = 'https://example.com/api'
data = {'key': 'value'}

response = requests.post(url, json=data)

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Example

This example shows how to send JSON data in a POST request to a test API and print the response status and JSON content.

python

import requests

url = 'https://httpbin.org/post'
data = {'name': 'Alice', 'age': 30}

response = requests.post(url, json=data)

print('Status code:', response.status_code)
print('Response JSON:', response.json())

Output

Status code: 200 Response JSON: {'args': {}, 'data': '{"name": "Alice", "age": 30}', 'files': {}, 'form': {}, 'headers': {'Accept': '*/*', 'Content-Length': '27', 'Content-Type': 'application/json', 'Host': 'httpbin.org', 'User-Agent': 'python-requests/2.31.0', 'X-Amzn-Trace-Id': 'Root=1-650d7d7f-4a1b2c3d5e6f7a8b9c0d1e2f'}, 'json': {'age': 30, 'name': 'Alice'}, 'origin': 'YOUR_IP', 'url': 'https://httpbin.org/post'}

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Common Pitfalls

Common mistakes when sending JSON data include:

Using data= instead of json= which sends data as form-encoded, not JSON.
Not setting the Content-Type header to application/json manually when using data=.
Passing a JSON string instead of a Python dictionary to json=.

Always pass a dictionary to json= to let requests handle conversion and headers.

python

import requests

url = 'https://httpbin.org/post'
json_string = '{"name": "Bob"}'

# Wrong way: passing JSON string to json= parameter
response_wrong = requests.post(url, json=json_string)

# Right way: passing dictionary to json= parameter
response_right = requests.post(url, json={'name': 'Bob'})

print('Wrong status:', response_wrong.status_code)
print('Right status:', response_right.status_code)

Output

Wrong status: 200 Right status: 200

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Quick Reference

Tips for sending JSON data in Python requests:

Use json= parameter to send JSON easily.
Pass a Python dictionary, not a JSON string.
requests sets Content-Type: application/json automatically.
Use response.json() to parse JSON response.

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Key Takeaways

Use the requests library's json= parameter to send JSON data easily.

Always pass a Python dictionary to json=, not a JSON string.

requests automatically sets the Content-Type header to application/json.

Use response.json() to read JSON responses from the server.

Avoid using data= for JSON as it sends form-encoded data by default.