Performance Tools

CDN Detection

Find out whether a website is delivered through a CDN, and which one.

Not sure what to enter? Try an example: cloudflare.com

Free & instant No signup How to use FAQ

Enter a URL to check its response headers for the signatures of common content delivery networks.

How do I know if a website uses a CDN?

CDNs such as Cloudflare, Akamai, Fastly or Amazon CloudFront leave recognisable traces in response headers (for example cf-ray or x-amz-cf-id) and in the server name. This tool checks those signals and names the CDN provider when it finds one.

How to detect a CDN

Enter the domain in the box above.
Click Detect CDN.
See which CDN, if any, was detected.
If none is used, a CDN can cut load times for visitors far from your server and absorb traffic spikes.

Related checks

To check how responses are cached, use the Cache Headers Checker.
To detect the site's other technology, use the Website Technology Checker.

A CDN serves your files from a location close to each visitor and soaks up traffic spikes. If no CDN was detected, a free plan from Cloudflare or your host is often enough - JustChecker monitors uptime either way.

Frequently Asked Questions

If your visitors are spread across countries, a CDN serves your pages from a location near each of them and absorbs traffic spikes. Local businesses with nearby visitors gain less.

Cloudflare's free plan is widely used, and several hosting plans include a CDN. Setup usually means changing nameservers or switching it on in the hosting panel.

Some CDNs don't add identifying headers, or you may be testing an address that bypasses it. Check that DNS points to the CDN.

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