Web & SEO
What is a content delivery network (CDN)?
A content delivery network (CDN) is a distributed set of servers that stores copies of your site's files and serves each visitor from the location nearest to them.
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Technical definition
A CDN caches static assets, and increasingly whole rendered pages, at edge locations distributed around the world. When a visitor requests a file, the request is routed to the nearest edge node. If that node holds a fresh copy it responds directly, avoiding a round trip to the origin server.
Beyond latency, a CDN absorbs traffic spikes that would otherwise reach the origin, and most providers bundle TLS termination, compression, image transformation, and protection against denial-of-service traffic.
In plain terms
Your server sits in one place. Your visitors do not. A CDN keeps copies of your site in dozens of places so nobody has to wait for data to cross an ocean.
It is the difference between ordering from a local warehouse and ordering from another continent.
Why it matters
For a business serving one town, a CDN is not the thing holding your site back. Your visitors are near your server, and image sizes and server response time matter far more.
It starts paying when your audience is spread out, when traffic is spiky, or when you sell to customers in other countries. The practical note is that you may already have one. Most modern hosting platforms include a CDN by default and do not make a point of it, so check what your host provides before buying a separate service.
