Caching and CDNs in plain English

Dear founder,

Caching and CDNs get talked about like dark arts. They're simpler than that, and understanding them helps you make sensible decisions without needing to become an engineer.

The plain version

• A cache keeps a ready-made copy of something so it doesn't have to be rebuilt every time
• A CDN stores those copies on servers around the world, so they load from somewhere near your customer
• Together they mean less waiting, especially for repeat visits and far-flung shoppers

Most hosted platforms handle a lot of this for you. The point isn't to configure it yourself, it's to know it exists so you can tell whether it's working.

Caching is just not doing the same work twice. A CDN is just keeping the answer close to the person asking.

What to check

• Are your images and assets served from a CDN?
• Do repeat visits feel instant, or are you rebuilding pages every time?
• Is anything accidentally uncacheable that shouldn't be?

You don't need the deep detail. You need enough to ask whether it's set up well, and to know when an answer sounds off.