Optimizely CDN: How Does It Work?


As a business owner, speed and efficiency is a vital part of customer satisfaction. No consumer intends to wait forever for your web pages or content to load. In fact, 70% of consumers in an Unbounce survey attest that page speed highly influences their willingness to make a purchase. And that’s essentially what a content delivery network (CDN) helps with.

A CDN is a set of distributed servers that deliver content based on proximity rather than the origin server. The result is faster load times, particularly for websites with a global reach and higher traffic.

This article delves into the role of Optimizely CDN and how you can leverage it to improve your business.

What is a CDN? The Vital Role of Content Delivery Networks.

Gartner defines CDNs as “highly distributed edge-based cloud delivery platforms that provide the following functionality: content acceleration, API caching, image optimization, streaming video delivery, web application, and perimeter security, and edge compute and storage.”

As previously mentioned, the principal purpose of a CDN is to improve web performance by speeding up the delivery of content and media. Additionally, the CDN architecture aims to reduce network latency caused by traffic flowing across multiple networks and long distances.

CDNs continue to grow in popularity, and most web traffic now goes through CDNs, including those of top enterprises such as Netflix, Amazon, and Facebook. To ensure faster content delivery, CDN vendors typically deploy dozens to hundreds of cache, storage, and compute nodes in their data centers (or those of third parties) around the world.

Suppose a user makes a webpage request, the CDN will route to the nearest server to deliver the cached content, and if there’s none, it connects with the origin server to provide the content and puts a copy down on the local/regional server so the next person from that region gets the cached copy. During the entire time, the user is unaware of this process.

Optimizely CDN: Two Separate Options, Or One Complete Option

Optimizely CDN users want to make their websites faster, and there are two ways to do that using Optimizely—which can cause some confusion.

Firstly, there’s Optimizely, the Digital experience platform/CMS CDN. This is the CDN that covers the entire Optimizely ecosystem, delivering your content and web experiences faster across the globe.

Secondly, there’s Optimizely Optimization CDN, which is a CDN specifically for Optimizely’s personalization and A/B testing functions, and not for other parts of the web experience.

These two separate products can be used independently or in tandem to improve the performance of the web experience.

So, how did this happen?

Before Episerver (the DXP/CMS) acquired Optimizely, Optimizely was an A/B testing and personalization tool. It offered multi-variate testing solutions. You could use it to optimize your website by leveraging specific user segments for personalization and A/B testing processing, among others. That helped enterprises build and experiment to better roll out, or roll back, web page elements.

Optimizely CDN for multi-variate testing helps to make your website faster by deploying its JavaScript testing snippets through a CDN, acting as an edge computing network. Through the CDN, the multi-variate content is stored closer to the end user geographically, cutting down on load times. But again, Optimizely CDN is designed specifically for those multi-variate testing content, and not for other elements or content blocks.

When using the CDN for your Optimizely CMS or DXP, cache your entire website, including images, CSS documents, JavaScript, and content, delivering them through regional CDNs rather than from your server.

Why Enterprises Are Opting for Optimizely CDN

The following are reasons why enterprises are increasingly adopting CDNs for their websites:

  • Low Google Lighthouse scores/slow loading times: A website that fails to improve will eventually lose customers to the most innovative and modern competitors. Given that Google is constantly changing its Lighthouse score algorithm, businesses need to look for options to optimize their website to meet customer needs. By using a CDN, you can ensure that your website’s UX responds faster, keeping you one step ahead of your competitors.
  • Poor SEO: There’s a direct correlation between improving your site’s discoverability for search engines and optimizing it for the web. Having trouble navigating a website or encountering errors may hinder visitors from taking action, leading to lower visibility and ranking. Some of the core SEO ranking factors include: optimizing page titles, improving loading speeds, enhancing user experience, including relevant keywords, and creating high-quality content. Using a CDN to improve your page load speed and user experience will ultimately lead to better SEO.
  • Ailing customer experiences that require multi-variate testing + optimization: By leveraging a CDN, an enterprise can rapidly deploy testing and optimization elements without affecting the page load speed. The CDN helps them cache the elements and deliver them from servers close to the consumer.
  • All of the above hitting enterprises’ bottom lines:Ultimately, if you don’t deliver content faster, you risk losing consumers and revenue too.

Considerations When Using a CDN

There are cases when caching with a CDN becomes a blocking factor in your application. If all of your dynamic logic runs at the origin server, and only static content is cached (CSS or images), then this may not be an issue for you.

Although not impossible, experimenting with heavily cached parts of an app can be tricky. There are times when it’s necessary to assign variations to dynamic requests. For instance, personalized content is dynamic, so ensure that you don’t cache them. More sophisticated CMS’s allow you to cache ‘parts’ of a page so that the parts that are dynamic aren’t cached, but the parts that are the same for all users can be cached.

Cached APIs should pull all variables from the URI rather than the header to prevent cached data from being displayed incorrectly and should be rigorously tested before going live. On the same note, never cache confidential or administrative content.

Building Faster & More Dynamic Experiences

Speed is a critical factor in delivering an excellent customer experience. Optimizely CDN offers users two options to improve content delivery for websites and multivariate testing. Enterprises can leverage the options individually or simultaneously to best serve their needs.

With CDNs, enterprises can ensure faster load times, better SEO and performance optimization, lesser resource usage, and higher reliability and availability. There are some occasions when you may want to reconsider using a CDN in the event it ends up negatively impacting your site. For more information on these, be sure to contact your Optimizely implementation partner or account manager.

Oshyn is an Optimizely implementation partner that has served several brands and agencies globally to deliver dynamic, immersive, and personalized web experiences. One such enterprise is TCDRS, which saw its bounce rate drop by 42.7% after Oshyn helped them replatform and implement Optimizely.

Interested in finding out how this happened? Check out the case study.