What is a CDN?

What it means

Without a CDN, every visitor downloads your site from one server in one place. Someone in Seattle loading a site hosted in New Jersey waits for the data to cross the country.

A CDN keeps copies of your images, stylesheets, scripts and sometimes whole pages on many servers in many cities. Each visitor gets the copy nearest to them.

The result is faster pages, less strain on your web hosting and better odds of staying up during a traffic spike.

How it works

Your main server is called the origin. The CDN’s servers are called edge servers, and the copies they keep are called the cache. A typical request goes like this:

1. A visitor requests a page, and DNS routes the request to a nearby edge server.
2. If the edge has a fresh copy, it sends it right away. That’s a cache hit.
3. If not, it fetches the file from the origin, sends it on and keeps a copy for the next visitor. That’s a cache miss.
4. Copies expire after a set time, or sooner if you clear (purge) the cache.

Many CDNs also filter bad traffic before it reaches your server. Some go further and run code at the edge: Lovable’s newer apps run on Cloudflare Workers, Cloudflare’s service for running code across its network.

Why it matters when you build a site

Speed is the main reason. A CDN cuts the time it takes for images and pages to arrive, which helps Largest Contentful Paint, one of Google’s Core Web Vitals. Google’s “good” mark is 2.5 seconds or less.

It matters more for some sites than others. A local plumber whose customers all live in one metro area gains less than a store shipping nationwide. But CDN service is often included or cheap, so there’s little reason to skip it.

A CDN also spreads the load. If a post takes off or a promotion sends a rush of visitors, the edge servers absorb most of the requests, so a modest hosting plan can keep up.

A CDN is also why static sites are so quick: finished files sitting on servers near every visitor.

How the big builders handle it

• Framer: hosting includes a global CDN alongside pre-rendering, image optimization and font subsetting.
• Wix: markets “multi-cloud hosting” and 99.99% uptime.
• Lovable: new apps run on Cloudflare Workers.
• v0 and Bolt: v0 deploys to Vercel’s infrastructure. Bolt hosts on Bolt Cloud, with Netlify as an alternative.
• Squarespace, Webflow and Shopify: the plan details we track don’t spell out CDN specifics. Hosting is included and run by the platform, so there’s nothing for you to set up.
• Self-hosted WordPress: your host may include a CDN, or you add one. On the WordPress sites we run, Cloudflare sits in front of the host and handles DNS and caching.

Common mistakes

• Caching pages that should never be cached. Carts, checkout, account pages and anything shown to logged-in users must be excluded, or one visitor can see another’s details.
• Forgetting to purge after an update. If you change a page and visitors still see the old version, clear the CDN cache.
• Losing DNS records when switching nameservers. Moving your nameservers to a CDN like Cloudflare means recreating every record. Check the email (MX) records before you switch.
• Expecting a CDN to fix a slow site. A heavy page served from nearby is still heavy. Shrink images and cut unneeded scripts too.

Related terms

• Web hosting: the origin server behind the CDN.
• DNS: how requests reach the nearest edge server.
• Core Web Vitals: the speed scores a CDN helps.
• Static website: the kind of site a CDN serves best.