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All Concepts
Performance & Scaling

CDN Explained

1

What is it?

<strong>CDN (Content Delivery Network)</strong> is a network of servers distributed globally that cache and deliver your website's content from locations closest to your users, dramatically improving load times and reducing server load.

2

Think of it like...

The Pizza Chain Analogy

Instead of ordering from the main kitchen across town (slow), you order from the nearest branch (fast). CDNs work the same way—serving content from the closest server to you.

🏠

Your House (User)

Wants pizza

🍕

Local Branch (CDN)

Nearby location

🏭

Main Kitchen (Origin Server)

Central location

3

Visual Flow

🌍User Request

Needs Content

Nearest CDN

Serves Cached Content

🖥️Origin Server

Fallback if Not Cached

4

Where you see it

1

User requests content

Browser requests image/video/file from your site

2

DNS routes to nearest CDN

Automatically finds the closest CDN server

3

CDN checks cache

If content is cached, serve it immediately

4

Fetch from origin if needed

If not cached, get from origin server and cache it

5

Deliver to user

Content served in milliseconds instead of seconds

5

Common Mistake

Wrong

"CDN is only for huge websites" or "CDN is just for images"

Correct

<strong>Any website benefits from CDN</strong>. It improves speed for all static content (HTML, CSS, JS, images, videos), reduces bandwidth costs, and provides DDoS protection.

💡 Real-World Example

Netflix using CDN:

1

Netflix has CDN servers in 1000+ locations worldwide

2

When you watch a show, it streams from a server near you

3

Without CDN: 2000ms latency from US to Australia

4

With CDN: 20ms latency from local server—100x faster!