API Fundamentals
/Intermediate
CDN Usage
Definition
Content Delivery Network. A globally distributed network of proxy servers that cache content physically closer to end users, providing high availability and extreme performance.
Explain Like I'm New
If your API server is in New York, a user in Tokyo has to wait 200 milliseconds just for the signal to cross the ocean. A CDN places 100 'mini-servers' around the world. The Tokyo user talks to a mini-server in Tokyo, getting the response in 5 milliseconds.
Real World Example
Cloudflare or AWS CloudFront. You put Cloudflare in front of your API. When users fetch `/api/static-product-list`, Cloudflare caches the JSON. The next 5 million users fetch it directly from Cloudflare, and your real server never even sees the traffic.
Common Use Cases
- •Global scaling
- •DDoS protection
- •Static asset delivery
Terminal Output
bash / terminal
/*
How a CDN intercepts an API request:
[ USER IN TOKYO ] ---> [ CLOUDFLARE NODE IN TOKYO ]
1. Does Cloudflare have a fresh copy of /api/products?
YES -> Return it instantly (5ms delay). Server doesn't know it happened.
NO -> Proceed to Step 2.
2. Cloudflare forwards the request across the ocean to the real server.
[ CLOUDFLARE ] ---> [ MAIN SERVER IN NEW YORK ]
3. Main Server generates the JSON and sends it back to Cloudflare.
4. Cloudflare saves a copy in Tokyo for the next user, and sends it to the user.
*/
Interview Questions
basic
- Are CDNs primarily used to cache static data (like images and blog posts) or highly dynamic data (like live bank balances)?
intermediate
- What does the term 'Edge Computing' mean in the context of CDNs?