Content Delivery Networks: Speeding Up Global Websites

Content Delivery Networks (CDNs) place copies of your site’s static assets on servers around the world. When a visitor loads your page, the CDN serves images, stylesheets, and scripts from the nearest location, reducing travel distance and latency. This simple change can dramatically improve page load times for users in different regions.

CDNs also help you handle traffic spikes, offload work from your origin server, and provide better reliability. If one region has a problem, requests can be served from another edge location while the issue is fixed. For many sites, a CDN is a practical first step toward faster, more stable delivery.

How CDNs work

Key ideas are edge servers, caching, and routing. An edge server stores copies of your assets. When a user requests a resource, the CDN checks its cache. If the item is fresh, it is served directly. If not, the CDN fetches from your origin, then stores the asset for next time. Over time, popular files stay longer at the edge, while rarely used ones are removed.

Caching rules matter. Set sensible cache TTLs for static assets, let the CDN validate with origin when needed, and purge assets when you update files. Versioning file names helps the edge keep old and new copies separate.

Choosing a CDN is about your audience. Look at geographic coverage, reliability, and how easy it is to purge or purge-by-version. Security features such as DDoS protection and TLS termination are also important for a fast, safe site.

Best practices include enabling modern compression (Brotli or gzip), supporting HTTP/2 or HTTP/3, and serving static assets without cookies whenever possible to improve cache hits. Use edge rules for dynamic content only when you have clear cacheable patterns and proper invalidation.

Tip: a small blog can start with a basic plan that caches images, CSS, and JavaScript. For a storefront or news site, place more dynamic API calls behind the CDN with careful cache headers and short TTLs to balance freshness and speed.

In short, a CDN makes your content closer to visitors, reduces load on your origin, and helps your site stay fast during busy times.

Key Takeaways

  • A CDN speeds up global websites by serving assets from nearby servers.
  • Proper caching rules and asset versioning prevent stale content while improving performance.
  • Choose a CDN with strong geographic coverage and security features to boost both speed and reliability.