Ask a non-technical professional what the most challenging part of their job is, and you’ll often hear, “Understanding what the heck our developers are talking about.” The “What the heck is . . .?” series explains common development terms in simple language. Today, we’re letting you know what the heck your developers are talking about when they talk about a “CDN.”
When developers talk about CDN (meaning: “content delivery network”), they’re talking about a linked group of web servers distributed across a wide geographic area. The same way you would set up multiple WiFi boosters in your home to make sure you could get a strong data connection in every room, developers rely on CDNs to provide their website customers fast and reliable access no matter where they live.
When you visit a website, it takes a certain time to load. And when you’re clicking around inside the website, it takes a certain time to react to your clicks. The delay between you asking the website to do something and it doing it is known as latency. The farther you are from the hosting server that is shuttling your request to the website and the website’s response back to you, the longer the latency. If you’re on your laptop in a cafe in New York City reading through the contestant bios for your favorite Japanese game show, your mocha might be ice cold by the time you scroll to the bottom of the page.
A CDN seeks to decrease latency by getting you closer to a website’s server. A CDN is built from two types of servers: an origin server and edge servers. The origin server houses the original copy of the website. It’s the starting point of the CDN. The edge servers are connected to the origin server and each other, but are scattered far and wide geographically. They store copies, or caches, of the website data. When you request information from the website, the CDN will send you to the closest edge server to get it. Closer servers mean quicker website responses!
Content delivery networks not only make website traffic faster, but also more resilient. A common type of cyberattack, a distributed denial-of-service (DDOS) attack, works by flooding a website server with data requests, overwhelming it and causing the site to crash. A CDN cushions the origin server by spreading the flood of data requests among the many edge servers.
The ability of a CDN to distribute and localize website data provides important benefits:
Upsun recommends Fastly as the preferred CDN partner for all projects. While self-service projects don't include a CDN by default, you can set up Fastly or Cloudflare at any time to deliver major performance improvements. Projects using a CDN enjoy faster loading times, increased traffic capacity, and enhanced security features.
Setting up a CDN is straightforward: simply configure your chosen provider and set up a custom domain. For Fastly specifically, you'll need your own Fastly subscription and can follow their official setup guide to get started. The process works with any Upsun project, giving you the flexibility to add CDN capabilities when you need them.
CDN providers like Fastly offer helpful features such as Anycast options for handling apex domains, while Cloudflare provides CNAME flattening. Both services include security features like HTTPS enforcement and protection against on-path attacks.
To learn more about setting up a CDN with your Upsun project, check out our CDN documentation or contact our team for guidance on choosing the right solution for your needs.