What is a CDN, and do you actually need one?
CDN gets thrown around like everyone already knows what it means. Here is the plain-English version — what it does, how it works, and an honest answer to whether your site needs one.
A CDN keeps copies of your site on servers around the world, so visitors load it from somewhere nearby instead of from your one origin server. The result is faster pages, less load on your server, and a site that doesn't fall over when traffic spikes. If you have visitors in more than one city, you probably want one.
CDN stands for Content Delivery Network, which is one of those names that technically tells you everything and practically tells you nothing. So let's skip the acronym and talk about the actual problem it solves.
The problem: distance is slow
Your website lives on a server somewhere. Say it's in Frankfurt. When someone in Frankfurt visits, the page arrives quickly — the data only has to travel a few kilometres. But when someone in Sydney visits, every request and response has to cross the planet and back, several times, just to load one page. Light is fast, but it isn't instant, and all those round trips add up to a site that feels sluggish on the other side of the world.
A single request from Sydney to Frankfurt and back is roughly 300 milliseconds of pure travel time. A page might make dozens of those round trips. That's where "slow" comes from — not your code, just geography.
The fix: bring the site closer
A CDN is a network of servers — called edge servers, or PoPs (points of presence) — spread across lots of cities. When you put your site behind a CDN, it keeps cached copies of your content on those edge servers. Now the visitor in Sydney loads your site from an edge server in Sydney, not from Frankfurt. Same site, a fraction of the distance.
It's not just about speed
Speed is the headline, but a CDN quietly does three other useful things:
So do you actually need one?
Honest answer: not everyone does. If your audience is entirely in one city and you get ten visitors a day, a CDN is a solution looking for a problem. But most sites aren't like that. Here's a rough guide.
| Your situation | CDN worth it? |
|---|---|
| Visitors in more than one country or region | Yes |
| An online shop where speed affects sales | Definitely |
| Occasional traffic spikes (launches, sales, press) | Yes |
| Lots of images, video or downloads | Yes |
| A tiny local site with a handful of nearby visitors | Probably not yet |
Rule of thumb: if you've ever thought "the site feels slow for some people" or "I hope it survives launch day", a CDN is the cheapest fix for both.
A CDN moves your content closer to your visitors and takes the load off your origin. It makes most sites faster and tougher, and getting started usually takes minutes. If your audience is spread out or your traffic is spiky, it's one of the highest-leverage things you can do.
The good news is that trying it doesn't require a migration or a rewrite. Point a zone at your existing site, and you'll see the difference on the very next page load.
See how NordicCDN does this for your site:
Mads has worked in IT — mostly hosting — since he was 16. He took an early stake in a SaaS company and helped grow it through to its acquisition by Visma, has built and run data-center networks, and served as CTO of a Danish data center. He started NordicCDN to make fast, secure infrastructure simple to use.
