CDNs are invaluable for a thousand and one reasons, but they are not fail-proof, sometimes causing end-user performance degradations. Considering that the global CDN market was around USD 10.9 billion in 2018 and is expected to reach approximately USD 24.9 billion by 2025, it is evident that business concerns spend a lot on it. It won’t, therefore, be reasonable to have their users tweeting about downtime and complaining online. It is, therefore, necessary for you to consistently monitor your CDNs and identify and leverage opportunities to optimize performance, to maximize your investments.

This article explains how to monitor and optimize the impact of a CDN on your website performance.

Monitoring and Optimizing Your CDN

A CDN that can troubleshoot some of the most common issues is excellent. What is better is a CDN that provides you tools to monitor your content delivery. However, this alone sometimes cannot entirely prevent the worst possible scenario. Proactive monitoring is, therefore, necessary. You must take care to identify a problem before users find out and degrade your brand on the internet. Besides, if you pay for CDN services, it is only right that you monitor it to evaluate if you are getting the promised services.

Apart from these, there are plenty of other good reasons why monitoring is essential regardless of the automation promised. These are examined below.

Monitor Your CDN with emphasis on Users Location

It is vital for you to monitor and optimize your CDN to tackle issues specific to certain locations. The very fact that a CDN is a CDN is an important reason why it should be monitored and optimized. Since content delivery is no longer done on just one server but distributed across various locations, it’s impossible to understand user experience in different geographies without monitoring. It is therefore probable that one of the edge nodes of the network to be down while the central server and other edge nodes are working perfectly fine. Another scenario may involve the CDN working well in urban areas, but not in rural areas, or the CDN not being compliant with the protocols used by a mobile phone network operator.

Therefore, if you only know the performance in a region, you may incorrectly assume that it is the same everywhere, thereby overlooking many of your users in other areas. Monitoring your end-user experience over a stable connection from each region where your content is being viewed is the best way to understand if you’re getting what you paid for with a CDN.

Optimize and Monitor Your Front End

If you don’t optimize your content before you ship it off to CDNs, of course, the consequence is unoptimized and underperforming contents for your users from your CDN. This negates the existence of the CDN since moving content closer to the end-user is meaningless if the content is unoptimized for an optimal experience. Using an optimizing CDN system like may alleviate this issue by taking dynamic action on whatever content you have provided them to create the best experience. However, if it is a grave error or even a human one, the CDN can only do so much.

Some of these errors are requiring the CDN to host overly large webpages, oversized images, unminified scripts, etc. Making sure your content is optimized is very important before you host it with CDN.

Examples of front-end optimization you can do are file compression and minification by making your webpages lighter and more manageable. This can be achieved by removing unnecessary HTML, CSS, and JavaScript characters. When the files are compressed, this reduces the total downloaded bytes, which save bandwidth and speeds download times.

Another front-end optimization you can incorporate is image management, which automatically transforms images based on the end-user device. Pre-fetching (Server Push) will also increase front-end optimization, and your users’ browsing experience can be significantly improved. Prefetching is the bundling of images, JavaScript, CSS, and more so end users can quickly navigate between pages while saving on load time. Pre-fetching also allows edge servers to send assets to end users before the request is even made.

Reducing external HTTP requests will also increase the loading time for your users. This includes eliminating features that may not be additive to the end-user experience, such as unnecessary JavaScripts, images, plugins, and excessive CSS.

Ensure CDNs are Mapping Properly

“Mapping” is the algorithm a CDN uses to decide which server is “closest” to you. This is very important because “closest” on the Internet is not always geographic miles but fiber/internet connection. CDN mapping is, however, a very complicated process that depends on various factors at any given second. Furthermore, many enterprises don’t have access to the working of their CDNs’ internal routing dynamics. Regardless, you can detect when your CDN’s mapping patterns is suboptimal and raise this to their attention. You can do this by measuring end-user performance to reveal what end users are experiencing. If there is a significant discrepancy in the time it takes to download similar content for a different user, then this is a sign the CDN’s mapping patterns are likely misconfigured.

Tools for Monitoring

There are quite a few ways in which you can monitor your CDN. You can use your CDN native monitor, use an Application Performance Monitoring (APM) Tool or a Real User Monitoring (RUM) Tool.

A good APM monitors your users’ quality of experience, assesses the impact of errors, unavailability, and degraded application response times on the user, pinpoint the origins of incidents, identify the causes of incidents and optimizes it.

On the other hand, a good RUM analyzes the performance of native, web, and hybrid apps and websites based on their real traffic and quality of experience. Measurements are made from the user side, and the RUM collects the response times of each page and compares them by users’ location and by users’ hardware and software (including browser) configuration. It also correlates performance with the number of visitors to identify any degradation during peak traffic periods.


No doubt, a CDN improves overall performance when it comes to content delivery. However, it would be best if you were on top of the game when it comes to managing site performance and user experience.

You can now use to optimize for global delivery easily with external monitoring tools.

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