CDN
Copies of your site stored around the world for faster loading.
What is CDN?
A Content Delivery Network stores copies of your app on servers worldwide. When someone in Tokyo visits your site, they get content from a nearby server instead of one in the US. This makes your app load faster everywhere.
You don't usually set up a CDN yourself. Vercel, Cloudflare, and Railway all include CDN functionality automatically.
In Vibe Coding
Vercel, Cloudflare, and Railway all include CDN functionality. When you deploy to Vercel, your static assets (images, CSS, JavaScript files) are automatically cached on a CDN worldwide.
Example
For example: Your landing page has a hero image. Without a CDN, every visitor downloads it from one server in Virginia. With a CDN, a visitor in London gets it from a London server in 20ms instead of 200ms.