Definition
A CDN (Content Delivery Network) is a network of servers spread across multiple locations worldwide that stores copies of your website’s files and delivers them to visitors from the nearest available server. Instead of every visitor requesting your images, stylesheets, and scripts from a single origin server, a CDN serves those files from a location geographically close to each visitor. This reduces the physical distance data needs to travel, which directly improves loading speed.
Why It Matters
Website speed has a measurable impact on both user experience and revenue. Studies consistently show that even a one-second delay in page load time increases bounce rates and reduces conversions. If your server is in London and a visitor is in Sydney, every request has to travel roughly seventeen thousand kilometres each way. A CDN eliminates that penalty by caching your content on servers in or near Sydney. Beyond speed, CDNs also provide resilience — if one server goes down, traffic is automatically routed to another, reducing the risk of downtime. Many CDNs include basic security features like DDoS protection as well.
Example
An e-commerce business based in Manchester sells products internationally. Their website is hosted on a single UK server, and customers in the United States and Asia report slow page loads. After adding a CDN, static assets like product images and CSS files are cached on servers in North America, Europe, and Asia-Pacific. Page load times for international visitors drop significantly, and the business sees an improvement in conversion rates from those regions.