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Content Delivery Network (CDN) tests

CDNs are widely used by large websites to distribute static content near to end users. This reduces the burden on the content providers' servers and improves web page load times. Major, well-known CDNs include Akamai, Google and Microsoft. There are a great many smaller CDNs in operation too.

The largest CDN operators will place caches inside ISP networks so that traffic does not even need to leave the ISP network. This is beneficial for both the ISPs (it reduces the load on their transit and peering links) and the CDN operators too (it spreads the content serving burden to a wider array of servers).

The SamKnows CDN test measures performance to multiple CDNs by fetching a small object (usually around 80KiB) over HTTP. Care is taken to ensure that the same object, or a very similar one in size and content, is fetched from each CDN, to provide comparability between the CDNs themselves.

CDNs currently supported for testing are as follows:

  • Google
  • Amazon AWS/Cloudfront
  • Microsoft Azure
  • Cloudflare
  • Akamai
  • Apple
  • Alibaba
  • Tencent
  • Fastly

The key metrics captured by the test are as follows:

  • TCP connection time
  • Download speed
  • Object fetch time (lower is better)
  • The IP address of the CDN node

Please note that the download speed is not representative of the maximum capacity of the user's broadband connection. An 80KiB transfer is not enough to ramp the line up to full speed. It is instead intended to be indicative of the transfer rate seen for a small object as served by the CDN in question.


Endpoint CDN Latency under otherwise-idle conditions. Many applications are served over a small number of CDNs. Not all CDNs have distribution endpoints in every country; this can affect the latency to applications hosted overseas.

Available CDN tests

Microsoft Azure

A cloud computing service created by Microsoft for building, testing, deploying, and managing applications and services through Microsoft-managed data centers.


A web infrastructure and website security company that provides content delivery network and DDoS mitigation services. Cloudflare's services sit between a website's visitor and the Cloudflare customer's hosting provider, acting as a reverse proxy for websites.


Apple operates its own CDN network for distributing video, apps, Mac OS X, and iTunes downloads.

Amazon AWS

Amazon Web Services is a subsidiary of Amazon providing on-demand cloud computing platforms and APIs to individuals, companies, and governments, on a metered pay-as-you-go basis.


The company operates a network of servers around the world and rents out capacity on these servers to customers who want their websites to work faster by distributing content from locations near the user.


Google Cloud Platform by Google, is a suite of cloud computing services that runs on the same infrastructure that Google uses internally for its end-user products.


Alibaba Cloud CDN (CDN) provides widely distributed nodes and allows you to deliver content, such as websites, audio, and videos. CDN allows users to download files from the nodes nearest to them, accelerating the response to user requests and increasing the success rate.


Tencent Cloud Content Delivery Network (CDN) is a delivery acceleration service that enables nearby access for end users by delivering content to cache nodes deployed worldwide.


Fastly is an American cloud computing services provider. It describes its network as an edge cloud platform, which is designed to help developers extend their core cloud infrastructure to the edge of the network, closer to users.