HTTP & Networking
What is a CDN?
A Content Delivery Network, a globally distributed cache of edge servers that serves your assets from the location closest to each user.
A CDN places copies of your static assets (images, JS, CSS, video, sometimes HTML) in points of presence (PoPs) around the world. When a user requests one of those assets, the request hits the nearest PoP instead of your origin server, dropping latency from hundreds of milliseconds to single digits.
Modern CDNs do more than caching. They terminate TLS at the edge, enforce WAF rules, run serverless functions on every request (Cloudflare Workers, Fastly Compute, Vercel Edge Functions), bot-detect, and DDoS-absorb. The line between "CDN" and "edge platform" has effectively dissolved.
For websites, the practical impact is that almost every production site sits behind Cloudflare, Fastly, AWS CloudFront, or a managed PaaS that includes one. If you're scraping, the CDN is what fingerprints your client, applies rate limiting, and presents you with the CAPTCHA, not the origin.
In the wild
- →Cloudflare caching
/static/main.cssat 300+ PoPs worldwide - →Vercel and Netlify serving Next.js static output through their built-in CDN
- →Akamai routing video segments through carrier-internal nodes for streaming services
How Brand.dev uses cdn
Endpoints in the Brand.dev API where this concept comes up directly.
FAQ
Do I need a CDN?
For any site with users outside your origin's region, yes. The latency win alone justifies it, and most CDNs have a generous free tier.
What's an edge function?
JavaScript or WebAssembly that runs on the CDN's PoPs instead of your origin. Useful for A/B tests, auth checks, and personalization that needs to happen before the cache.
Why do scrapers struggle with CDN-fronted sites?
Because the CDN, Cloudflare especially, runs bot detection, JS challenges, and rate limiting before the request ever reaches the origin. You're fighting the CDN, not the site.
Related terms
The application protocol the web is built on, a simple request/response format for asking a server for a resource.
HTTP encrypted with TLS, the same protocol, but every byte on the wire is authenticated and protected from eavesdroppers.
The cryptographic protocol that encrypts and authenticates network traffic—the security layer under HTTPS, SMTPS, and most modern protocols.
A server-side policy that caps how many requests a client can make in a given window, returning 429 Too Many Requests when the cap is exceeded.
A challenge-response test designed to distinguish humans from bots, usually presented as image, audio, or behavioral puzzles.