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CDN Check

Which CDN served a URL, from which edge, whether it was a cache hit — and how much sooner the first byte arrived than at the origin.

The same path, reached without the CDN — to measure what the CDN saves.

Monitor CDN Check automatically

Which CDN served a URL, from which edge, whether it was a cache hit — and how much sooner the first byte arrived than at the origin. NetTests can run this check on a schedule, preserve historical results, compare changes over time, and alert you the moment something breaks.

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Frequently Asked Questions

What does CDN Check tell me?

Which Content Delivery Network (CDN) answered the request, from which edge location, and whether the response came from its cache. Give it your origin URL as well and it measures how much sooner the first byte arrives through the CDN than straight from the origin — the saving the CDN actually delivers.

Which CDNs does it recognise?

Cloudflare, Amazon CloudFront, Fastly, Akamai, Vercel, Netlify, Bunny CDN, Azure Front Door and Google's edge, from the headers each one sends. It also recognises Amazon S3, Google Cloud Storage and GitHub Pages as origins.

What counts as a cache hit?

A response served from the CDN's cache at any layer, without waiting on your origin. When a CDN has two layers (an edge and a shield), a hit at the shield still counts: your origin did not have to answer. A miss, a revalidation, a bypass or a response the CDN marks as dynamic does not count.

Why might my CDN hit here but miss for my visitors?

The check runs from one location, so it sees the edge nearest to that location. Each edge keeps its own cache, so a page that is cached in one region can still miss in another. Schedule the check in a report to see the hit rate over time.

What should the origin URL be?

An address that reaches your origin without the CDN — for example the load balancer's hostname, an origin subdomain or a storage bucket URL — for the same path. It must be publicly reachable.

Related Report Tools

These tools and monitors cover the same area — worth checking if you're already here.