How to Set Headers in Python Requests: Simple Guide

To set headers in python requests, pass a dictionary of headers to the headers parameter in the requests.get() or requests.post() function. For example, use requests.get(url, headers={'User-Agent': 'my-app'}) to send custom headers with your request.

Syntax

Use the headers parameter in the requests methods to add custom HTTP headers. The value must be a dictionary where keys are header names and values are header values.

• url: The web address you want to request.
• headers: A dictionary of header names and values.

python

import requests

response = requests.get('https://example.com', headers={'User-Agent': 'my-app/1.0'})

Example

This example shows how to send a GET request with a custom User-Agent header and print the response status code and headers sent.

python

import requests

url = 'https://httpbin.org/headers'
headers = {'User-Agent': 'my-app/1.0', 'Accept': 'application/json'}

response = requests.get(url, headers=headers)
print('Status code:', response.status_code)
print('Response JSON:', response.json())

Output

Status code: 200
Response JSON: {'headers': {'Accept': 'application/json', 'Host': 'httpbin.org', 'User-Agent': 'my-app/1.0', 'X-Amzn-Trace-Id': 'Root=1-...'}}

Common Pitfalls

Common mistakes when setting headers include:

• Not using a dictionary for headers.
• Using incorrect header names or casing (headers are case-insensitive but should be spelled correctly).
• Overwriting default headers unintentionally.
• Passing headers as a list or other data type instead of a dictionary.

Always pass headers as a dictionary and check the spelling of header names.

python

import requests

# Wrong way: headers as a list (will cause error)
# response = requests.get('https://example.com', headers=['User-Agent: my-app'])

# Right way:
response = requests.get('https://example.com', headers={'User-Agent': 'my-app'})

Quick Reference

Tips for setting headers in Python requests:

• Headers must be a dictionary: {'Header-Name': 'value'}.
• Use standard header names like User-Agent, Accept, Authorization.
• Headers are case-insensitive but use common casing for readability.
• Pass headers to requests.get(), requests.post(), etc., via the headers parameter.

Key Takeaways

Pass headers as a dictionary to the headers parameter in requests methods.

Use correct header names and values to avoid request errors.

Headers customize your HTTP request, like setting User-Agent or Authorization.

Avoid passing headers as lists or other incorrect types.

Check response to confirm headers were sent correctly.