Why Use a CDN? Here Are 10 Data-Driven Reasons

By Brian Jackson
Updated on September 1, 2022
Why Use a CDN? Here Are 10 Data-Driven Reasons

Perhaps not to anyone's surprise, but here at KeyCDN, one of the most frequently asked questions we get from visitors is "Why Use a CDN?" A CDN has a lot of other advantages besides simply speeding up your content delivery. Today we want to dive more in-depth into answering that question and share with you 10 data-driven reasons why you should be using a content delivery network (CDN) if you aren't already and how it can help your website stay ahead of the competition.

Why use a CDN?

If you aren't familiar with what a CDN (content delivery network) is, then we encourage you to first read our post that describes how a CDN works. Many of the top brands and website today are using CDNs because they serve global audiences and need a way to deliver their content fast. According to BuiltWith, over 41% of the top 10,000 websites are using a CDN. If we take a look at the top 100,000 we can see that number drops significant, which is not necessarily a good thing. We have found that in most cases, even smaller businesses don't realize just how much a CDN can benefit them.

Web page sizes are growing rapidly as the internet gets faster and media becomes more and more part of our daily lives. According to data provided by HTTP Archive, the average web page size in 2010 was 702 kB compared to 2,409 kB in 2016.

Average page size - 2010

Average page size - 2016

With the increase in size of every web component and the addition of video, webpage size has increased by 1,707 kB or 243% from 2010 to 2016. Read more below about how a CDN can help combat the slow load times that frequently accompany websites due to the rapid growth of web page sizes. We will also share additional advantages of using a CDN, besides just the performance factors.

1. Faster performance and lower latency

Of course, the very first reason to use a CDN is because it provides an easy way to increase the speed of your websites while also lowering the latency. Ilya Grigorik, a web performance engineer at Google said:

Using a CDN allows us to terminate the connection close to the user, which can significantly reduce the cost of TCP and TLS handshake. For best results, you should be using a CDN to serve both static and dynamic content.

We interviewed 60+ web performance experts a while back and we asked them about common mistakes they see people making when it comes to web performance. Andreas Grabner, a performance expert at Dynatrace, mentioned that a common one is that people don't have proper cache layers (browser, CDN, web server and app server).

Speed without a CDN

We ran a few quick tests on a fresh version of WordPress running the twenty sixteen theme. Each test was run 5 times and the average was taken. We first ran the test with the KeyCDN speed test tool without a CDN enabled. The test was ran from Frankfurt Germany as our origin server is located in Chicago, IL. This was to more effectively show you how a CDN can help dramatically increase speeds over long distances for global audiences. Our average total load time was 1.3 seconds.

Speed with a CDN

We then ran 5 additional tests from the same location with a CDN, KeyCDN, enabled on the WordPress website. Our average total load time was 646 ms.

From simply deploying a CDN we saw a decrease in total load times by 50.31%! We also ran latency tests in a previous post in which we saw an average of a 83% decrease in website latency when using a CDN, as opposed to not using one.

2. Traditional web bosts can't keep up

A while back we wrote a post comparing the differences between CDN hosting and traditional web hosting. To be frank, current technology and traditional web hosting is no longer capable of meeting the demands of websites. A CDN, made up of edge servers which are deployed in different parts of the world, now play a significant role in surpassing the computing resources of traditional web hosting in order to deliver rich and high quality multimedia content in a reliable and cost-effective way.

CDNs now are responsible for a majority of the load on a lot of websites. This can allow for savings on your web host, and also less of your resources being used. We pulled data from a client's site below for an example.

Bandwidth with web host

In the last 7 days they have used 6.85 GB of data with their web host.

Bandwidth with content delivery network (KeyCDN)

In the last 7 days, they have used 14.6 GB of data with KeyCDN.

That means the content delivery network is handling 68% of the load. And remember, unlike a web host where everything is on one server, this is spread across a global network of POPs with more than a thousand servers. So by using a CDN you can take the load off of your origin server.

3. SEO advantages

When it comes to search engine optimization (SEO) page speed is a very important factor as it pertains to page rankings. Most search engines consider the page loading time in their formulas. Google loves fast websites and announced in 2010 that website speed would begin to affect search engine rankings. The faster your website is, the better chance you have moving up in SERPs.

Accelerating websites is extremely important. Faster websites mean satisfied customers. PageSpeed becomes significant for rankings.

- Matt Cutts

Another SEO advantage that is often overlooked is Google image search. By optimizing your website to load faster with a CDN, it will increase the frequency in which Google crawls your images, in turn allowing your images to be more widely available and indexed faster in Google. How fast is your website? Use a website speed test tool to determine if you need to spend more time on optimization. Generally aiming for 2 seconds or less is a good goal.

4. More affordable than you think

Another common misconception is that CDNs are associated with a large price tag. And indeed with some CDN providers that is true. However, with KeyCDN, the prices are very affordable (see CDN pricing page). With the speed increases you see, it is definitely worth the small investment.

Generally the cost of bandwidth is cheaper than that with a traditional hosting provider. And as you saw above, when using a CDN, it generally takes at least 60%+ of the load off of your origin server. You can decrease your bandwidth even more by using advanced CDN features such as Origin Shield and hotlink protection.

5. Reliability

Most of you have probably encountered your website going down at one point or another, which can be very frustrating. Whenever adding additional third parties into the mix, such as a CDN, it is true that there is now another point of failure. However, because of how a CDN's architecture is setup, it actually provides reliability. With a CDN requests to your website are always routed to the nearest available POP. If one happens to be down, it simply passes the request onto the next one. This creates redundancy to ensure less downtime and a pleasant web experience.

6. Traffic spikes and scalability

When it comes to the web, you never know when you could get a traffic spike. Whether you are appearing on a show like Shark Tank or hit the top of Reddit, it is always important to be prepared for the worst. Most web hosts will cripple under heavy loads. A CDN can help you avoid that issue. Since your website's static content (which often accounts for 80% or more) is cached on the edge servers, this takes an enormous load off of the origin server. With the majority of resources now being delivered via the content distribution network, your origin server doesn't have to work as hard.

This allows your website to be much more scalable with minimal effort and avoid any downtime scenarios which could actually cost you money.

7. Better security and DDoS protection

A CDN can provide additional security. Since 60%+ of the traffic is being served through the CDN provider, they will mitigate DDoS attacks for you on their edge servers. KeyCDN has very powerful custom protocols in place to handle large mitigations.

Other advanced CDN security features include SSL and Secure Token. By enabling SSL you are ensuring that everything is encrypted between the CDN edge servers and the origin server. KeyCDN offers shared SSL, custom SSL, and Let's Encrypt SSL options depending on your preference. Secure Token allows you to generate secured links with an expiration time. After it has expired people can no longer access that content.

8. Simple integrations

In most cases, CDNs can be easily deployed on almost any platform in just a matter of a few minutes. There are numerous integration possibilities, whether you are running WordPress, Drupal, Joomla, or even a custom framework such as Laravel or Zend Framework. Make sure to check out KeyCDN's 40+ CMS integration guides and framework integration guides.

For example, if you are running WordPress, you can use the free lightweight WordPress CDN Enabler plugin and get your CDN implemented with 5 easy steps.

  1. Create a Pull Zone in the KeyCDN dashboard.
  2. Install the CDN Enabler plugin (log in to your WordPress dashboard: Go to Plugins -> Add new).
  3. Activate the plugin and click on settings.
  4. Enter the CDN URL or Zone Alias in the CDN Enabler Settings (you can find the CDN URL in the KeyCDN dashboard).
  5. Save the settings and verify in the HTML code if your assets are loading from the CDN.

9. Better conversion rates and sales

It has been proven time and time again that boosting your speed can increase your conversions. This is mainly due to the fact that you are providing a better user experience. About 46% of users will not return to a poorly performing website. And 74% of users will abandon after waiting 5 seconds for a mobile site to load.

Mobify also did a recent case study on the affect of mobile website speed. They discovered the following:

  • For every 100 ms decrease in homepage load speed, Mobify's customer base saw a 1.11% lift in session based conversion, amounting to an average annual revenue increase of $376,789.
  • For every 100 ms decrease in checkout page load speed, Mobify's customers saw a 1.55% life in session based conversion, amounting to an average annual revenue increase of $526,147.
  • An increase of one pageview per user results in a 5.17% lift in user based conversion, i.e. for each additional page viewed per user, Mobify saw their average customer's annual revenue increase by: $398,484.

So as you can see, every part of your website should be optimized, from your homepage all the way down the marketing funnel to your checkout page. By using a CDN you can ensure your assets are delivered fast across your entire funnel.

10. Lower costs

As we mentioned earlier, a CDN in most cases will be handling over 60% of your website's bandwidth, which in return reduces the load/costs on your origin server. But another way to prevent costs from going out of control is by enabling hotlink protection. This means you can prevent others from embedding your assets, such as images on other websites. A great example of this recently was when an author on the Huffington Post website copied and pasted images from the Oatmeal's website, a popular comic website. This ended up accruing the Oatmeal owner a bill of over $1,000 from AWS. In this case, if hotlink protection would have been enabled, he could have blocked the author from using his images on the Huffington Post website costing him a large amount of money.


Why use a CDN? Well, as you can see there are many ways a CDN can help benefit your website. Besides drastic performance improvements, you can also expect to see SEO advantages, better conversion rates, and a better overall experience for visitors; especially for those located further away from your origin server. If you have not yet had a chance to try a CDN, we urge you to give KeyCDN a try and test the before and after results for yourself!

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