What is a CDN?

Websites use a CDN so that pages, images, and video reach visitors from a server nearby instead of crossing half the planet. CDNs now serve a large portion of all internet content, from web pages and images to software downloads and streaming video. Adoption is mainstream: Cloudflare, the largest CDN and reverse-proxy service, alone serves 24.2% of all websites (W3Techs, July 2026).

How a CDN works

A CDN places edge servers at points of presence (PoPs) in cities around the world, each holding cached copies of a site's static files — images, CSS, JavaScript — pulled from the origin server where the site actually lives. A visitor's request routes to the nearest PoP. On a cache hit, the file is served straight from the edge in milliseconds; on a cache miss, the PoP fetches it from the origin, delivers it, and stores a copy for the next visitor.

Distance is the heart of the trick: data can't outrun the speed of light through fiber, so all else being equal, a shorter network path means lower latency. All else is rarely equal, though — congestion, cache status, and server load matter too — which is why a CDN doesn't simply pick the geographically nearest server. Instead, it combines edge caching with algorithmic routing that steers each request to the best available edge, plus load balancing to spread the work across the network.

What a CDN improves

Three things, mainly: speed, capacity, and cost. Shorter distances mean better load times; requests spread across many servers mean traffic spikes don't pile onto one machine; and every cached response that skips the origin trims bandwidth costs. The gains are measurable: Bunny CDN, the CDN DreamHost offers, advertises up to 40% faster load times from its 119 points of presence (checked July 2026).

Most CDNs also double as a security layer. Many bundle firewalls that filter malicious requests before they reach your site, and the distributed network itself blunts DDoS attacks: a flood of junk traffic spreads across dozens of PoPs instead of concentrating on your origin server.

CDN providers and costs

The commercial providers you'll meet most often are Cloudflare, Akamai, Amazon CloudFront, Fastly, and Bunny CDN — the one DreamHost sells. You don't always have to pay: Cloudflare, for example, has long offered a permanent free plan, and paid plans typically bill by CDN traffic volume in monthly GB or TB tiers rather than a flat fee. CDNs also come in other forms: private CDNs that large organizations build in-house, and peer-to-peer networks where users' devices help deliver the content.

Many hosts bundle a CDN with hosting. DreamHost includes Bunny CDN's Essential tier with every DreamPress plan at no extra charge and offers it as an add-on to other hosting plans — see DreamHost's CDN feature page for current plans and pricing. Choosing a provider yourself? How To Use a CDN With WordPress (Plus 10 Popular Providers) compares the popular options and walks through setup.

CDN vs. web hosting

A CDN doesn't replace your web host — it sits in front of it. The two do different jobs:

• Web host: stores your original site files and runs the application. It's the origin server — the single source of truth for your content.
• CDN: stores cached copies of that content at edge locations and serves them from closer to each visitor. Anything not in the cache still has to come from the origin.

Take away the host and there's nothing to deliver; take away the CDN and the site still works, just more slowly for far-away visitors. A site that uses a CDN needs both.

When a CDN is worth adding

Add a CDN when your visitors are far from your server, your pages are media-heavy, or a traffic spike is a real risk — a product launch, a viral post, a seasonal rush. It adds the least when your audience and your server sit in the same region and the site is small and mostly text; solid server-side caching may already do the job. The next step costs nothing: check whether your current hosting plan already includes a CDN or supports one as an add-on.