Python: Bypass CloudFlare 'Verifying Browser' in Requests

Usually you can make HTTP requests on CloudFlare-protected websites, but depending on their Security Level (as I'm Under Attack!), your requests won’t pass their firewall.

Making requests via command-line you may get the response 503 Service Unavailable, it means your script is stopping at this page:


This is a client-side JavaScript algorithm to determine legitimate traffic, since command-line scripts don’t execute JS code, you’re never redirected. To bypass we need to make our requests run whatever JS code there is, to behave just like a web browser.

The ‘make it yourself’ way

Use PyExecJS to run JS code in Python, you’ll still need extra work to evaluate CloudFlare protection. Interesting module though.

The ‘ready to use’ way


pip install cfscrape

import cfscrape

# Requests wrapper
requests_flare = cfscrape.create_scraper()
r = requests_flare.get("")  # or post()
r.status_code  # 200
  • If you’re getting a CAPTCHA instead (common for TOR exit nodes), this technique won’t work.
Written on September 30, 2016