What is a CDN (content delivery network)?
A CDN, or content delivery network, is a group of servers spread across many locations, each holding a copy of your website. A visitor is served from the copy nearest to them, so the page arrives sooner than if every request had to travel to one machine in one country.
Why it matters to a shop
Most of your customers are nearby, so a CDN changes less locally than the advertising suggests. Two moments are where it earns its place: someone looking you up from abroad — a tourist planning a trip, a supplier checking you exist — and a sudden rush, when a post gets shared or a local paper mentions you. Without one, that is the day the site falls over in front of the largest audience it will ever have.
Three things to check
- Find out whether you already have one, before you buy a second. Hosting plans and site builders often include caching or a delivery network already, without calling it that on the invoice — read what is in the plan you are paying for before you pay for another.
- Shrink your photos before you upload them. A photo straight off a phone is several megabytes; a CDN delivers it faster but never makes it smaller. For a shop site, resizing images beats buying a CDN almost every time.
- After you change a price or swap a photo, open the live address in a private window. A cache can keep handing out the old copy — know how long that lasts, and how to clear it.
Common mistake: Buying a CDN to rescue a slow site whose real problem is a 10 MB photo on the home page. A CDN moves your files faster; it does not make them smaller.