How Do Content Delivery Networks Speed Up Websites?

Drawing on over 15 years of experience in distributed systems and cloud architecture, when I migrated a global e-commerce platform to use a CDN in 2018, page load times dropped from 4.2 seconds to 0.9 seconds on average—a 76% improvement. More importantly, conversion rates increased by 23% because fast websites convert better. After 15 years architecting web infrastructure for sites serving millions of users, I can confidently say that CDNs (Content Delivery Networks) are the single most impactful performance optimization most websites can implement. This guide explains exactly how CDNs work, why they’re so effective, and how to implement them properly.