What is a CDN?

A content delivery network, or CDN, is a group of servers spread across the world that each keep a copy of your website. When someone opens your site, they're served from the location nearest to them — not from one machine in one city on the other side of the planet. That's the whole idea, and it's the single biggest reason a modern website can feel fast everywhere at once.

The problem a CDN solves

Every website lives on a computer somewhere. Without a CDN, that "somewhere" is a single place. If your server is in one city and your visitor is an ocean away, every click has to travel the full distance there and back — and the internet, fast as it is, still can't beat the speed of light. Distance turns into waiting.

It's not only speed. A single location is also a single point of pressure: one machine handling a traffic spike, one power outage away from being unreachable, one busy afternoon from slowing to a crawl. A CDN takes that single point and spreads it out.

How a CDN actually works

Picture your site published once. The network takes that one copy and distributes it to locations all around the world — often called edges or points of presence. From then on, when a visitor requests a page, the request is routed to the nearest edge, and that edge answers directly. The animation below shows both halves of the story: your site is copied out to the edges once, then each visitor is served from the closest one.

Replay

Caching: ready before it's asked for

The mechanism that makes this work is caching. Each edge keeps a ready-to-serve copy of your pages, images, and styles. Because the content is already sitting at the edge, it doesn't have to be fetched from a central server on every visit — it can be handed over immediately. For a site published with a static-first tool, almost everything can be cached this way, which is why it stays fast even under a rush of visitors.

Routing: finding the nearest edge

The other half is routing — getting each request to the right edge without you configuring anything. A well-built network uses anycast routing so that a single address is answered from many locations at once, and each request naturally takes the shortest available path to whichever edge is closest. You don't pick a region; the network picks for every visitor, continuously.

What a CDN gives you in practice

• Speed everywhere — visitors are served locally, so the page starts loading sooner whether they're one city or one ocean away.
• Resilience — with copies in many places, there's no single machine whose failure takes your site offline. Traffic reroutes to the next nearest healthy edge automatically.
• Room to grow — a sudden spike in visitors is spread across the whole network instead of landing on one server.
• Security at the edge — because requests pass through the network first, it can help filter malicious traffic before it reaches your site.

CDN vs. web hosting — what's the difference?

People often ask whether a CDN replaces web hosting. Traditionally they were separate: you hosted your site on one server and bolted a CDN in front of it to speed things up. On a modern network the line disappears — the network both stores your site and serves it from the edge, so the CDN isn't an add-on, it's how the hosting works. That's the model behind Just Web Hosting: your site doesn't live in one place with a delivery layer in front; it lives on the network.

Do you need to set any of this up?

No. This is the part worth stressing: a good CDN is invisible. There are no regions to choose, no caching rules to write, no certificates to install. When you publish a site with Just Publish, it's distributed across 330+ cities the moment it goes live, served over automatic HTTPS, with nothing for you to manage. The network does the distributing, routing, and caching quietly underneath.