CDNs 101: An Introduction to Content Delivery Networks
summary
CDNs power 50–70% of internet traffic (much higher for video) and cut egress bills: examples show CloudFront dropping ~$0.12/GB to ~$0.085/GB, Azure from ~$0.18 to ~$0.125, Cloudflare often zero. Practical techniques include TTL caching, serve-stale-if-error to survive origin outages, Lambda@Edge/Cloudflare Workers for JWT-based cache key variation, on‑edge image resizing with sharp, and PartyKit-style multiplayer at the edge. Main gotchas: set-cookie can cause cache poisoning, vary headers (Vary) and align origin logic with CDN cache keys.
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chapters (14)
- 0:00Start
- 7:17Egress costs
- 10:19Caching
- 12:07Reliability
- 14:06Latency
- 16:31DDoS Protection
- 18:51Flexibility
- 32:22What is "The edge"
- 35:18HTTP Methods
- 36:35Types of caches
- 40:44'Vary' header
- 43:24HTTP Fundamentals Summary
- 46:18Avoiding cache poisoning
- 49:39You can put your SPA config in your API!
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