Overview
There are a variety of ways you can check to see if Cloudflare is working on a website.
Viewing headers
View the following article for information on how to view your website's headers:
Since Cloudflare inserts header information into requests, you’ll need a way to check these headers to see if Cloudflare is enabled and working on your website.
When looking at these headers, you’re looking for the following specific Cloudflare header:
CF-Cache-Status: HIT