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Cloudflare Detector

Check any public website to see whether it uses Cloudflare.

Public signal scan
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Scan a website

Enter a URL and Stackcrawler will inspect public technology signals.

Websites using Cloudflare

Browse real website examples detected with Cloudflare.

View examples

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What we check

Stackcrawler looks for public page markers, scripts, platform fingerprints, metadata, and other visible implementation clues.

How can you detect if a website is using Cloudflare by looking at the source code?

Detecting whether a website is using Cloudflare involves examining specific elements in the website’s source code, HTTP headers, and other accessible information.

Here’s a step-by-step guide on how to do it:

  1. Open the Page Source: Right-click on the webpage and select “View Page Source” or press Ctrl+U (Windows) or Cmd+Option+U (Mac).
  2. Look for Cloudflare-Specific Tags and Scripts: Use Ctrl+F (Windows) or Cmd+F (Mac) to search for keywords like cloudflare and cf- in the source code. Look for: <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>.
  3. Check HTTP Response Headers: Open your browser’s developer tools by pressing F12, and navigate to the “Network” tab. Reload the page to capture network data. Check for Server: cloudflare.
  4. Search for JavaScript Variables and Functions: Scan the source code for JavaScript variables and functions specific to Cloudflare: Cloudflare, __cf, cf.beacon, and cf_cookie.