Apart from creating great content (for humans, not search engines) and building authority via backlinks, we’ve seen in the previous section, that improving your website’s load speed is another crucial factor in improving both the user experience and your chances of ranking better in the SERPs. Implementing CDN’s play a huge role in optimising the page speed of your website and improving your SEO.

What Is A CDN?

A CDN (Content Delivery Network) is a system of edge servers (also referred to as POPs) that are distributed across the world. CDNs store and cache a copy of your website’s static content. These assets are then served by the various edge servers based on the user’s geographical location. This allows for uninterrupted delivery of large amounts of content to users.

If for example your website is hosted in London, then people who are accessing it from Manchester or Birmingham will receive the content much quicker than users accessing it from Sydney or Tokyo.

Essentially, the further away the person accessing your site is (i.e. the distance between the server and a client), the longer it will take them to load your site – this naturally can be frustrating for users. CDNs therefore offer businesses and webmasters the opportunity to reach a wider audience regardless of their location within seconds.

As a result, CDNs are and should be an essential priority for any business that is looking to grow their search presence.

What’s the Difference Between Static and Dynamic Content?

Static content is any file that is stored in a server such as a HTML, JavaScript or image file, and remains the same every time that it is displayed to the user. Think of static content like a book or newspaper in that once it’s been published, it doesn’t change and is the same for everyone who buys a copy.

Dynamic content is the opposite – it adapts based on certain factors that are specific to every user. For example, the time of visit, location and device used may influence what you see.

Dynamic web content will not look the same for every user, in fact, it can also change whilst users interact with it.

How Do CDNs Work?

As explained above, CDNs are made up of distributed servers called POPs (or “points of presence”), which are spread out across the world. The server closest to where the user accesses your website is referred to as the edge server. Users accessing your website are connected to the closest edge server which ensures that the content on the website is delivered to the user as quickly as possible.

The below four steps outline a typical CDN caching process:

1. When the user requests a web page, the user’s request is routed to the CDN’s nearest edge server.

2. The edge server requests the origin server for the content that the user wants.

3. The origin server responds to the edge server’s request.

4. The edge server responds to the client with the content.

By caching the website’s content on a CDN, you are able to present your website’s content to the user quicker than you would be able to from your host server. On top of this, CDNs remove and update the static content on a regular basis which ensures that only the most relevant and fresh content is being delivered to clients, regardless of whether or not the website content is cached.

How Are CDNs Beneficial For SEO?

CDNs have various effects on your SEO, here we’ll outline a few ways that your website’s search presence can be heightened by a CDN.

Improved Site Load Speed

A factor we have discussed in some detail already, CDNs help minimise the latency between content being delivered from your server to the client. Load speed is crucial in providing the user with a great experience, improving conversion rates and decreasing the bounce rate.

If you’re sceptical about site speed being a ranking factor, take it from Google: “We encourage you to start looking at your site’s speed… not only to improve your ranking in search engines, but also to improve everyone’s experience on the Internet.”

Ensures Content Consistency

CDNs purge content through the use of caching algorithms and canonical headers so that only the most recent and relevant content loads first. This means that duplicate content creation is minimised.

Improved Security

Adding a CDN to your website serves as an extra layer of security and the risk of an attack will also decrease. This is because of the multiple servers that are located across the world which work together by sharing the load time to prevent your site from crashing.

Improved Availability and Uptime

Hosting the static content on a CDN means there’s less strain on your own server – this means that your website’s uptime and availability will increase. On top of this, most of the top CDN providers have built in mechanisms to prevent your site from going down, for example load balancing ensures that your website stays online whenever it receives a sudden spike in visitors.

What CDN Should You Use?

When choosing which CDN to use for your website, we recommend that you look for the one that offers the best performance and features (like load balancing) at a price that is suitable for your budget. There are lots of CDN providers out there such as Sucuri, MaxCDN, Azure, Amazon CloudFront, and most are incredibly easy and simple to set up.

At SUSO, we use CloudFlare, which we’ll take a look at in more detail next.