CDN
A CDN (Content Delivery Network) is a globally distributed network of servers that delivers content like images, videos, and web pages closer to the user, drastically reducing load times.
What Is a CDN?
A Content Delivery Network (CDN) is a globally distributed network of edge servers that delivers static and dynamic content as close to the end user as possible. Instead of sending every request to a central origin server, content is cached at edge locations and served from there. This reduces latency, increases availability, and offloads the origin server.
How Does a CDN Work?
Edge Locations and Caching
A CDN operates hundreds or thousands of edge locations worldwide. When a user requests a web page, the request is routed to the nearest edge server. If the requested content is already cached, it is served directly (cache hit). Otherwise, the edge server fetches the content from the origin server and stores it for future requests (cache miss).
DNS-Based Routing
CDNs use DNS-based routing to direct users to the optimal edge server. Factors such as geographic proximity, server load, and network health influence the routing decision. The result: minimal latency and maximum performance for every user, regardless of location.
CDN Provider Comparison
- Amazon CloudFront: Deeply integrated into the AWS ecosystem with over 400 edge locations worldwide and seamless S3 integration.
- Cloudflare: Comprehensive CDN with integrated WAF, DDoS protection, and Workers for edge computing – powerful even in the free tier.
- Akamai: The pioneer among CDNs with the largest edge network, particularly suited for enterprise customers.
- Fastly: Real-time CDN with programmable edge logic via VCL and WASM, ideal for dynamic content.
Benefits of a CDN
Performance
A CDN can reduce your website's load times by 50-70%. Especially for international audiences, geographic distribution is crucial – a user in Singapore shouldn't have to wait for a server in Frankfurt.
Security
Modern CDNs offer integrated security features such as DDoS mitigation, Web Application Firewall (WAF), bot detection, and SSL/TLS termination. The origin server is shielded by the CDN and is not directly reachable from the internet.
Scalability
CDNs absorb traffic spikes without requiring additional infrastructure provisioning. Whether Black Friday, product launch, or viral campaign – the CDN scales automatically with traffic.
CDN Configuration Best Practices
Set sensible cache TTLs for different content types: long TTLs for static assets (images, CSS, JS), short TTLs for dynamic content. Use cache invalidation or versioned file names for immediate updates. Enable compression (Brotli or Gzip) and HTTP/2 or HTTP/3 for optimal performance.
CDN for Mid-Market Companies
A CDN makes sense for mid-market companies too – not just at millions of page views. Even with a nationally distributed user base, a CDN measurably improves user experience. CloudFront or Cloudflare can be set up with minimal effort and offer excellent value for money.
Frequently asked questions about CDN
Yes, you benefit from a CDN even within Germany. Edge servers are distributed across the country and deliver content faster than a single hosting server. CDNs also provide DDoS protection and offload your origin server during traffic spikes.
CDN costs are typically based on data transfer volume. Cloudflare offers a free plan for small websites. CloudFront charges from approximately $0.085 per GB. For mid-market websites, monthly costs typically range between 10 and 100 euros.
Positively. Google considers Core Web Vitals like Largest Contentful Paint (LCP) as a ranking factor. A CDN significantly improves these metrics through faster load times. Higher availability is also positively evaluated by search engines.
Yes, modern CDNs also optimize dynamic content through persistent connections to the origin, TCP optimization, and edge computing. CloudFront and Fastly support Edge Functions that execute dynamic logic directly at the edge.
Related terms
Related services
Last updated: April 2026