How to Find What CDN a Website Uses (5 Methods)

Content Delivery Networks power the fastest websites on the internet, caching and serving content from edge servers around the world. Knowing how to find what CDN a website uses is useful for competitive research, performance optimization, troubleshooting, and migration planning. We've identified CDNs for thousands of domains, and the good news is that CDNs leave clear fingerprints in DNS records, HTTP headers, and IP addresses that make identification straightforward.

Quick Answer: To find what CDN a website uses, check the HTTP response headers using browser developer tools or curl -I. Look for CDN-specific headers like CF-Ray (Cloudflare), X-Cache + Via (CloudFront), X-Served-By (Fastly), or X-Vercel-Id (Vercel). You can also run a DNS lookup and check if CNAME records point to a CDN's domain, or use a hosting checker to identify the provider automatically.

#What Is a CDN?

A CDN (Content Delivery Network) is a distributed network of servers that caches and serves website content from locations geographically close to visitors. Instead of every request traveling to a single origin server, the CDN delivers cached copies from the nearest edge server — reducing latency, improving load times, and absorbing traffic spikes.

#How CDNs work

1. A visitor requests example.com/image.jpg
2. DNS resolves the domain to the CDN's nearest edge server (not the origin)
3. If the edge server has the file cached, it serves it immediately (cache HIT)
4. If not cached, the edge server fetches it from the origin, serves it, and caches it for future requests (cache MISS)

Major CDNs operate hundreds of edge locations worldwide. Cloudflare has 330+ data centers, AWS CloudFront has 450+ edge locations, and Fastly operates 90+ PoPs (points of presence).

#Method 1: HTTP Response Headers (Most Reliable)

CDNs inject distinctive headers into every response they serve. Checking these headers is the most reliable way to detect which CDN a website uses.

#How to check

curl -sI https://example.com

Or in the browser: open Developer Tools (F12) > Network tab > reload > click the first request > Response Headers.

#CDN header signatures

Each CDN has unique headers that identify it:

#Reading the headers

Here's an example response from a Cloudflare-proxied site:

HTTP/2 200
server: cloudflare
cf-cache-status: HIT
cf-ray: 8a1b2c3d4e5f-LHR
age: 3600

This tells you: the site uses Cloudflare, the response was served from cache (HIT), the edge server is in London Heathrow (LHR), and the cached content is 1 hour old.

#Method 2: DNS Record Analysis

CDNs require DNS records that point to their infrastructure. Checking CNAME records and nameservers reveals CDN usage.

#How to check DNS

Use our DNS lookup tool or the command line:

dig CNAME www.example.com +short

#CDN DNS patterns

CNAME records often chain through multiple levels. When we run this against real domains, we frequently see a domain CNAME to cdn.example.com, which CNAMEs to d1234.cloudfront.net — the final destination reveals the CDN.

For more on reading DNS records, see our guide on how to find DNS records for any domain.

#Method 3: IP Address Range Lookup

Every CDN operates from known IP ranges. By resolving a domain's IP and checking which network owns it, you can identify the CDN.

#How to check

1. Resolve the domain's IP:

dig +short example.com A

2. Look up the IP's owner:

whois 104.16.132.229 | grep -i "org\|netname"

#Common CDN IP ranges

Our hosting checker automatically resolves the domain's IP and identifies the provider — including CDN detection. Enter any domain to see if it's served from a CDN and which one.

#Method 4: Browser Developer Tools

You can detect CDNs directly in your browser without command line tools.

#Steps

1. Visit the website
2. Open Developer Tools (F12 or Cmd+Option+I)
3. Go to the Network tab
4. Reload the page (Cmd+R or Ctrl+R)
5. Click the first request (the main document)
6. Inspect Response Headers for CDN signatures

#What to look for

Beyond the main document, check requests for static assets (images, CSS, JS). In our experience, many sites use a CDN only for static assets while serving the HTML from the origin. Look at the domain and headers of these secondary requests — they often point to CDN subdomains like static.example.com or cdn.example.com.

#Method 5: Page Source and Asset URLs

Sometimes CDN usage is visible directly in the page's HTML source.

#Common patterns in source code

<!-- Cloudflare-specific script -->
<script src="/cdn-cgi/scripts/abc123/cloudflare-static/rocket-loader.min.js"></script>
 
<!-- CloudFront distribution -->
<img src="https://d1234abcdef.cloudfront.net/images/logo.png" />
 
<!-- Bunny CDN pull zone -->
<link rel="stylesheet" href="https://example.b-cdn.net/styles/main.css" />
 
<!-- Cloudflare challenge page (when under attack mode) -->
<noscript>Enable JavaScript and cookies to continue</noscript>

The /cdn-cgi/ path is unique to Cloudflare — no other CDN uses it. Asset URLs containing CDN domains (*.cloudfront.net, *.b-cdn.net, *.azureedge.net) directly reveal the CDN for static content.

#Common CDNs and Their Use Cases

Not all CDNs serve the same purpose. Here's how the major players compare:

#When a Website Uses Multiple CDNs

Some websites use different CDNs for different purposes:

• Main site on Cloudflare (proxy + security)
• Video content on AWS CloudFront (media delivery)
• Third-party scripts loaded from Google's CDN (ajax.googleapis.com)

To detect all CDNs on a page, check the Network tab in developer tools and filter by domain. Each unique external domain may be served from a different CDN.

#Frequently Asked Questions

#Can I tell if a website uses a CDN without any tools?

Yes. If a website loads extremely fast from different geographic locations, it likely uses a CDN. However, for definitive identification, checking HTTP headers or DNS records is necessary — fast performance alone doesn't confirm CDN usage, as the origin server could simply be well-optimized.

#What if no CDN headers appear: does that mean no CDN is used?

Not necessarily. Some CDN configurations strip or rename identifying headers. Enterprise Akamai setups, in particular, can be configured to remove default headers. However, DNS and IP analysis will still reveal the CDN in most cases.

#Does using a CDN hide the actual hosting provider?

When a CDN proxies traffic (like Cloudflare in proxy mode), the IP address resolves to the CDN, not the origin host. The actual hosting provider is hidden at the IP level. To find the origin host, check WHOIS records, DNS history, or non-proxied subdomains. See our guide on finding a website's hosting provider for more methods.

#Is it possible for a website to use no CDN at all?

Yes. Many smaller websites serve all traffic directly from their origin server. This works fine for sites with a regional audience and moderate traffic. However, as traffic grows or the audience becomes global, a CDN becomes increasingly important for performance and reliability.

#Looking Ahead

Multi-CDN strategies are becoming mainstream, with larger sites routing traffic through two or more CDN providers for redundancy and performance optimization. At the same time, edge compute platforms are blurring the line between CDN and hosting — services like Cloudflare Workers and Deno Deploy run application logic at the edge, making traditional CDN detection methods less clear-cut. Expect CDN-agnostic tooling and observability platforms to grow as teams need unified visibility across increasingly distributed delivery networks.

#Wrapping Up

Identifying a website's CDN is a matter of knowing where to look. HTTP response headers are the most reliable method — every major CDN injects unique identifiers. DNS records and IP range analysis provide additional confirmation, while browser developer tools offer a visual approach that requires no command line knowledge.

Enter any domain into our hosting checker to detect CDN usage alongside DNS records, IP geolocation, SSL certificate details, and hosting provider information — all from a single lookup.

#Related Articles

• How to Check If a Domain Uses Cloudflare
• How to Check Website Server Location
• What Is My Website's IP Address?
• How to Find Out Who Hosts a Website