What is CDN (Content Delivery Network)?
A network of servers worldwide that serves your static content (images, CSS, JavaScript) from locations close to your users, making your site load faster.
In plain English
Instead of one warehouse shipping products globally (slow, expensive), you stock inventory in distribution centers worldwide. When someone orders, it ships from the nearest center. A CDN does the same with your website's files — serving them from the nearest server to each user.
How it works
Your static files (images, CSS, JavaScript, fonts) are distributed to servers around the world. When a user in Tokyo loads your site, static files come from a server in Tokyo instead of your origin server in Virginia. This reduces latency from hundreds of milliseconds to single digits for static content.
When you already have one
If you're on Vercel, Netlify, or Cloudflare Pages, you already have a CDN. These platforms automatically serve static assets from their global network. You don't need to configure anything — it's built in.
When you need more
If you host on a traditional server (Railway, Render, DigitalOcean), your static assets are served from one location. Add Cloudflare in front of your domain for CDN caching, DDoS protection, and performance optimization. It's free for most use cases and takes about 15 minutes to set up.
Frequently asked questions
Do I need a CDN for my app?
If you're on Vercel or Netlify, you already have one. If you're on a traditional server and your users are geographically distributed, a CDN significantly improves load times. For apps with a local user base (all users in one region), the benefit is smaller but still worthwhile for DDoS protection.
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