CDN
Content Delivery Network - distributed servers that deliver content from locations near users.
What is CDN?
A Content Delivery Network (CDN) is a network of servers distributed globally that caches and delivers content from locations geographically close to users. This reduces latency by minimizing the physical distance data travels.
Modern CDNs offer more than caching - including DDoS protection, edge computing, automatic optimization, and SSL termination. Popular CDNs include Cloudflare, Fastly, and AWS CloudFront.
Why CDN matters
CDNs dramatically improve load times for global audiences. A user in Tokyo accessing a US-hosted site might see 200ms latency - with a CDN serving from Japan, that could be 20ms. CDNs also reduce server load and improve reliability.
How to implement
Choose CDN provider
Configure DNS to route through CDN
Set up caching rules
Configure SSL certificates
Purge cache when content updates
Monitor CDN performance
Common mistakes to avoid
- Not using CDN for static assets
- Caching dynamic content that shouldn't be cached
- Not purging cache after updates
- Serving all content from single origin
Examples
Static assets (images, CSS, JS) cached at edge
HTML pages cached with appropriate headers
API responses cached at edge for read-heavy endpoints
Frequently asked questions
Even small sites benefit from CDNs. Free tiers from providers like Cloudflare offer caching, security, and performance improvements with minimal setup.
Hosting is where your origin server lives. CDN is a layer that caches and serves content from multiple locations. CDN doesn't replace hosting - it works with it.