Content Delivery Networks: Speeding Up the Web

Content Delivery Networks (CDNs) place copies of your content in many locations around the world. This makes pages load faster for visitors who are far from your main server. CDNs handle many requests at once and serve content from a nearby edge location. They also help your site scale during sudden traffic surges.

How they work: When a user requests a file, the CDN routes the request to the closest edge server. If the edge has a fresh copy, it serves immediately. If not, it fetches from the origin, stores a copy, and serves it. Popular files stay near users, while less-used content stays on the origin until needed.

Why use a CDN: Lower latency improves user experience. It saves bandwidth on your origin, reduces peak load, and increases reliability during traffic spikes. Many CDNs also offer image and video optimization, and security features such as DDoS protection and edge TLS termination. Some providers include easy analytics to see how your content travels.

Key features: edge caching, cache rules, purge APIs, dynamic content acceleration, geo routing, and support for HTTP/2 and HTTP/3. For media, optimization can shrink file sizes with little quality loss. Security options include a web application firewall and edge TLS certificates. Edge compute lets you run small tasks close to users.

Getting started: choose a provider, add a CDN endpoint, and point your domain with a CNAME. Set caching rules (long TTL for static assets with versioned names), enable compression, and enable HTTP/2/3. Test from different regions and measure timing. Plan for DNS propagation and monitor for any cache misses after changes.

Best practices: use versioned filenames, set cache-control headers, and cache fonts, scripts, and images at the edge. Avoid dynamic content on the edge unless needed. Monitor cache misses and purges, and keep security settings up to date. Regular reviews of cache settings and purges help maintain fast load times.

Key Takeaways

  • CDNs reduce latency by serving content from edge locations.
  • They save bandwidth and improve reliability during traffic spikes.
  • Use proper caching rules and versioning to maximize benefits.