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Performance

Content Delivery Network

CDN

Portrait of Lukas Horvath, co-founder of Roelu Studio
Lukas HorvathCo-founder

What is Content Delivery Network?

A Content Delivery Network (CDN) is a globally distributed network of servers that caches copies of website assets — HTML, images, JavaScript, CSS, video — in data centres close to visitors. When someone visits the site, content is served from the nearest edge location instead of the origin server. This cuts latency, improves load times, and absorbs traffic spikes. Cloudflare, Vercel, Fastly, and AWS CloudFront are common CDN providers.

Why it matters

Without a CDN, every visitor to your site pulls every byte from your origin server — which might be in Frankfurt, Virginia, or wherever your hosting provider parked it. A visitor in Tokyo pays a 250-millisecond tax on every request just for the round trip. Multiply that by every image, font, and script on the page and the result is a slow, expensive site for anyone outside the origin region. A CDN fixes that for roughly the price of a streaming subscription. There is no scenario in 2026 where a production website should be running without one. If your hosting provider doesn't include a CDN, switch providers.

How it works

When you put a site behind a CDN, the CDN provisions edge servers in dozens to hundreds of locations worldwide. The first time someone in, say, Singapore requests your homepage, the CDN fetches it from the origin, caches it at the Singapore edge, and serves it. Every subsequent visitor from that region gets the cached copy — milliseconds away instead of continents. Static assets cache aggressively. Dynamic content uses smart invalidation rules. Modern platforms like Vercel and Cloudflare Pages build the CDN in by default — you deploy once and your site is global. No configuration, no extra cost, no excuses.

Related terms

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  • Image Optimization

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  • Core Web Vitals

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