Content Delivery Networks for Global Delivery

Content Delivery Networks (CDNs) place servers in many locations worldwide. By serving content from near users, they cut travel time and improve page load speed. This helps visitors engage with your site, especially when they are far from your origin server.

How CDNs work

CDNs keep copies of your files on edge servers. When someone asks for a resource, the CDN serves it from the closest edge node. If the file isn’t cached, the edge fetches it from your origin and stores it for future requests. Time-to-live (TTL) values decide how long content stays in cache, and purges clear outdated items.

Geolocation routing directs users to the best edge location. Modern CDNs also terminate TLS at the edge, support HTTP/2 or HTTP/3, and protect against traffic spikes. These features help deliver images, scripts, video, and even API responses faster.

What to deliver with a CDN

  • Static assets: images, CSS, JavaScript, fonts
  • Media files and video streams
  • API responses and dynamic content acceleration
  • Secure delivery with TLS at the edge and strong DDoS protection

Choosing a CDN

  • Coverage for your target regions and mobile networks
  • Real-world performance data in key cities
  • Easy integration with your hosting and build process
  • Security features, such as TLS, WAF, and rate limiting

Start simple: point your static assets to the CDN, keep origins for dynamic pages, and monitor results.

Best practices

  • Set Cache-Control and ETag headers with sensible TTLs
  • Version assets to invalidate caches safely
  • Enable compression (gzip or Brotli) and image optimization
  • Purge or invalidate when asset updates occur
  • Avoid caching sensitive pages or user data

Measure impact

  • Track latency to different regions and cache hit rate
  • Compare page times before and after the switch
  • Monitor availability during traffic spikes
  • Use real-user monitoring to verify improvements

Example: a site with many images and scripts benefits from lower latency across continents, especially in Europe, Asia, and the Americas.

Key Takeaways

  • CDNs reduce latency by delivering content from edge locations near users
  • Proper caching and asset versioning prevent stale content and improve reliability
  • Choose a CDN based on regional coverage, real-world performance data, and security features