Performance Tools

CDN Detection

Detect whether a website uses a common CDN provider.

Enter a domain to detect whether it uses a common CDN provider (Cloudflare, CloudFront, Fastly, Akamai, and more).

More Performance Tools

Page Size Checker Performance Health Score Keep-Alive Checker Render-Blocking Resources Checker Cache Headers Checker Image Optimization Checker HTTP Version Checker GZIP Compression Checker

JustChecker tracks your website's performance signals continuously.

What Is CDN Detection?

A CDN (Content Delivery Network) serves a website from servers close to each visitor. This tool looks at response headers for fingerprints of common CDNs: Cloudflare, Amazon CloudFront, BunnyCDN, Fastly, Akamai, Google Cloud CDN and Azure CDN.

When to Use It

To confirm a CDN is active after setting it up.
To find out how a competitor delivers their site.

How to Use It

Enter the domain.
See which CDN, if any, was detected.

Understanding the Result

Detection is based on clear signs such as a cf-ray header (Cloudflare) or x-amz-cf-id (CloudFront).

Limitations

Smaller or custom CDNs, and CDNs configured to hide their headers, may not be detected.

Headers That Reveal a CDN

CDN	Typical headers
Cloudflare	`cf-ray`, `server: cloudflare`, `cf-cache-status`
Amazon CloudFront	`x-amz-cf-id`, `x-amz-cf-pop`, `via: ... cloudfront`
Fastly	`x-served-by`, `x-cache`, `x-timer`
Akamai	`x-akamai-transformed`, Akamai-specific `server` values
BunnyCDN	`server: BunnyCDN`, `cdn-cache`

Why Use a CDN

Speed: files are served from a location near each visitor, cutting latency for international traffic.
Load: cached files never reach your server, so it handles more visitors.
Protection: most CDNs absorb DDoS traffic and can add a web application firewall.
Modern features: HTTP/3, Brotli and image optimisation are often one setting away.

Is the CDN Actually Caching?

A detected CDN is only half the story. Look at cache headers such as cf-cache-status: HIT or x-cache: Hit from cloudfront. A MISS or DYNAMIC on every request means pages are passing straight through to your server.

Check caching rules with the Cache Headers Checker and response headers with the HTTP Headers Checker.

Frequently Asked Questions

It looks for recognizable signatures in HTTP response headers, IP address ranges, and other technical fingerprints that major CDN providers characteristically leave, rather than requiring any special access or configuration on your part.

Some CDN configurations deliberately strip or obscure identifying headers for security-through-obscurity reasons, or use a less common provider whose fingerprint this tool doesn't yet specifically recognize.

A CDN serves content from servers geographically closer to each visitor (reducing latency), absorbs traffic spikes and some attack traffic, and often provides built-in compression, caching, and TLS termination - a broad performance and reliability improvement.

Smaller sites with a geographically concentrated audience benefit less dramatically, but for any site with a global or geographically dispersed audience, a CDN is generally considered a meaningful, low-effort performance improvement.

Yes - a CDN typically means the public-facing IP address resolves to the CDN's edge infrastructure rather than your actual origin server's IP, which is expected and intentional.