SeeTheStackSeeTheStackA content delivery network caches a site's pages and files on servers around the world. Every CDN stamps its responses: Cloudflare adds a cf-ray header, CloudFront an x-amz-cf-id, Fastly and Akamai their own cache headers. The site's DNS often points at the CDN too, through a CNAME or the CDN's nameservers, and the IP address belongs to the CDN's network. We check the homepage's headers, DNS and IP owner against each CDN's markers.
Many sites use more than one: a platform's own CDN for the page and a second one for images or scripts. We list each CDN that serves the homepage itself.
Limits: a CDN used only for images or downloads on another hostname doesn't show up here. The full report for the site lists every third-party domain the page loads.
Paste the address above. We fetch the homepage, read the response headers and look up the site's DNS and IP owner, then match them against the markers each CDN leaves.
Usually, yes. The CDN answers every request, so the real server's address stays private. The hosting checker says so when that's the case.
Yes. Large sites often split traffic between CDNs, or use one for pages and another for images and video.
Yes. There's no sign-up and no limit on lookups.
Share of the 6,676 scanned sites where we found a CDN or host.
Amazon CloudFront5%
Varnish Cache4%
CDN770.1%
Gcore CDN0.0%
