What is Content Delivery Network (CDN)?

CDNs reduce latency by serving content from edge servers near users instead of a distant origin server. They cache static assets (images, CSS, JavaScript, fonts) and can also cache dynamic content with proper configuration. Major CDN providers include Cloudflare, Fastly, Akamai, and AWS CloudFront. CDNs also provide DDoS protection (absorbing attack traffic across their network), SSL/TLS termination, image optimization, and web application firewall (WAF) capabilities. Configuration involves pointing DNS to the CDN, setting cache rules (TTL, cache keys), and defining origin pull behavior. Modern CDNs support edge computing (running code at edge locations) for personalization and A/B testing.