What is a Content Delivery Network (CDN)?

A Content Delivery Network (CDN) distributes content across geographically dispersed servers, serving requests from the location closest to each user.

How CDNs work:

1. Your content is uploaded to the CDN origin server

2. CDN replicates it to edge servers worldwide

3. When a user requests the content, the CDN routes them to the nearest edge server

4. The content loads faster due to reduced physical distance and optimized routing

CDN benefits for email:

Faster image loading: Recipients worldwide get images from nearby servers rather than your single origin.

Reliability: CDNs handle traffic spikes easily. A big email send won't overwhelm the hosting.

Uptime: Multiple servers provide redundancy. If one fails, others serve the content.

Bandwidth offloading: CDNs handle the traffic instead of your primary infrastructure.

Popular CDNs: Cloudflare, AWS CloudFront, Fastly, Akamai, Google Cloud CDN

Many ESPs use CDNs behind the scenes for hosted images. If managing your own, ensure proper HTTPS configuration and set appropriate caching headers.

It's having warehouses in every major port. Cargo gets retrieved from the nearest location rather than shipped across the world each time.