Glossary

What Is a CDN?

A CDN (Content Delivery Network) is a distributed network of servers deployed in multiple geographic locations worldwide. When a visitor loads your website, a CDN serves your site's files from the server location closest to that visitor — instead of from a single origin server that might be located far away.

How a CDN Works (Simply)

Without a CDN:

  • Visitor in Tokyo requests your website
  • Request travels to your origin server in, say, Chicago
  • Files travel back from Chicago to Tokyo
  • Adds 150–300ms of network latency on every page load

With a CDN:

  • Visitor in Tokyo requests your website
  • CDN detects a cached version of your files in Tokyo (or nearest PoP)
  • Files served from Tokyo
  • Latency drops to 10–30ms

CDNs cache static files — HTML, CSS, JavaScript, images — that don't change with every request. Dynamic content (logged-in user data, real-time pricing) typically bypasses the cache.

CDN Cost

ProviderFree TierPaid PlansBest For
Cloudflare✅ Generous free plan$20–$200+/moMost websites; simplest setup
AWS CloudFront❌ Pay-per-use~$0.01–$0.02/GB + requestsAWS ecosystem
Fastly❌ Pay-per-useVolume-basedDeveloper-focused, high-performance
BunnyCDN~$0.01/GBBudget, high-performance
Cloudflare R2 + CDNVolume-basedStorage + CDN combined

For most websites, Cloudflare's free plan is the correct starting point. It provides CDN, SSL, basic DDoS mitigation, and DNS management at no cost.

What CDNs Are Included With Hosting

Many managed hosting providers include CDN in their plans:

  • Kinsta, WP Engine: Cloudflare or proprietary CDN included
  • SiteGround: Cloudflare integration available
  • Cloudways: Cloudflare Enterprise integration available

Hosted website builders (Squarespace, Wix, Shopify) include CDN infrastructure automatically.

When Paid CDN Makes Sense

  • High-traffic sites where bandwidth costs compound (CDN can reduce origin bandwidth significantly)
  • Global audience requiring low latency across multiple continents
  • Security-focused requirements (enterprise DDoS, WAF, bot mitigation)
  • Video delivery at scale (specialized video CDNs like Bunny Stream)

CDN and Security

CDNs also serve as a security layer. Cloudflare's free plan includes:

  • Basic DDoS protection (mitigates common volumetric attacks)
  • SSL/TLS termination (handles your HTTPS certificate)
  • IP reputation filtering
  • Basic bot detection

See our Website Security Cost guide for a fuller breakdown of security stack costs.