What is CDN in Web Development?

If you’re new to the world of web development, you may be wondering what a CDN is and how it fits into the internet ecosystem. CDN stands for Content Delivery Network and is the term given to a group of servers spread across the globe. Data stored for websites on these servers can be served with perfect optimization based on the visitor’s location.

One of the most common applications for a CDN is to deliver stylesheets and JavaScript files of popular libraries and frameworks like jQuery, Tailwind CSS, and more.

In today’s article, we’re answering what is CDN in web development. We’ll explore what you need to know about CDNs if you are learning web development, from a brief history of the technology, to how a CDN works under the hood. Let’s get into it!

What are CDNs Used For?

Various libraries, including Bootstrap, jQuery, etc., deliver stylesheets, HTML, and JavaScript files via CDNs. An organization’s own servers are less burdened when libraries’ static assets are served over a CDN.

CDNs can also be used to return cached static page files. If a user visits your site, the data will be cached in the CDN so it can be accessed quicker in the future. As you can imagine, every business wants to reap the benefits of using a CDN to serve content faster. As a result, CDNs are extremely popular with major companies and content creators of all calibers.

History of CDNs

CDNs sprang from the wave of new internet technology in the 1990s. While early websites were simple HTML files, they soon grew more advanced. As websites became more cumbersome, companies and users needed a way to serve content faster. And just like that, the CDN was born.

A CDN can be considered to have gone through three generations in its evolution: Static, Dynamic, and Multi-purpose. Each generation of CDN evolves with new capabilities, technologies, and concepts, introducing new elements to its network architecture. As CDN services became mainstream, their pricing trended down along with each generation.

How do CDNs Work?

With a CDN, you can cache your website’s content in multiple geographic locations (also known as points of presence, or PoPs) to minimize the distance between your website and visitors. The content is delivered to visitors within a PoP by several caching servers.

The caching servers are responsible for storing and delivering cached files. They are primarily used to reduce bandwidth consumption and speed up the loading of websites. It is typical for CDN caching servers to have multiple storage drives and high RAM capacities.

For content delivery networks to work, CDN caching is essential. Rather than using the original files for subsequent requests, a copy of the files is stored on the caching server and used instead of the originals. How it works is fairly straightforward.

Your web page receives an end user’s first request for static assets. As soon as the assets have been delivered to the end user, they are cached and stored near the end user on the caching server at the PoP. The next time the same user requests the same assets, the requests aren’t sent to the origin server. Requests are instead sent to the cached files on the PoP server to see if the assets are still available.

Generally speaking, your content is distributed across multiple locations, providing your users with better coverage. A visitor in California, for example, can access your Europe-based website via a PoP situated in the US. This is much faster than having the visitor’s request and response travel across the whole world.

What are the Most Popular CDNs?

Ever since the introduction of the first CDNs, many companies have sprung up to offer their own content delivery services. So what are the most popular networks today?

Generally speaking, you can rank different CDNs based on their global scale, latency, security, and cloud compatibility. Some CDNs also offer advanced analytics like website performance, audience behavior, and other key performance indicators.

Today’s most popular CDNs include Azure CDN, Amazon Cloudfront, Cloudflare, CDN77, and Google Cloud CDN. Among WordPress users, Cloudflare and Bunny CDN have the most loyal users. In particular, Cloudflare is recommended repeatedly in many online forums.

What is the Difference Between CDN and Hosting?

In web hosting, websites are hosted on a server; users access them via the Internet. When the server is located on the other side of the world, the user must wait for the data to be retrieved. On the other hand, content delivery networks are more about expediency; they can accelerate the delivery of content from a website to users.

There is also a difference in the number of servers used between the two. While traditional web hosting relies on a single server, a CDN utilizes a network of edge servers or Points of Presence that deliver content from multiple interconnected servers.

Traditional web hosting distributes 100% of the website’s content to users. CDNs, on the other hand, only deliver the most vital parts of static and dynamic content. Since it accesses the closest server geographically, it performs much faster.

How to Link to a CDN?

If you’re learning web development, you might want to link to a CDN of a popular library like jQuery. With just one line of code, you can add all the functionality of a specific library to your website or project.

All you must do is locate the library or framework’s CDN address. For example, if you wanted to add jQuery to your site, you would include a link within the <head> of your document:

<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.6.0/jquery.min.js"></script>
</head>

The process is very similar if you want to link to a CSS library like Bootstrap or Tailwind CSS. Just add a link to the CDN within the <head> of your document:

<head>
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap@4.3.1/dist/css/bootstrap.min.css" integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous">
</head>