How to Use a Content Delivery Network (CDN)

· Category: Web Performance

Short answer

A CDN distributes your content across geographically dispersed servers. Users download assets from the nearest edge node, reducing latency.

Steps

  1. Choose a CDN provider such as Cloudflare, Fastly, or AWS CloudFront.
  2. Upload static assets or configure the CDN to proxy your origin server.
  3. Set cache rules for different file types.
  4. Enable HTTP/2 or HTTP/3 on the CDN.
  5. Monitor cache hit ratios and adjust TTLs accordingly.

Tips

  • Use a CDN for dynamic content with edge caching or serverless functions.
  • Purge the cache immediately when deploying updates to static assets.
  • Geographic routing can also improve availability during outages.

Common issues

  • Cache invalidation delays may cause users to see stale content.
  • Misconfigured SSL certificates on the CDN cause browser security warnings.