Why a CDN matters more than it looks

The advice here is unglamorous, which is probably why it gets skipped. A CDN is easy to treat as a detail, and that is exactly why it is worth a few minutes of attention.

Performance work is mostly subtraction, which makes it unpopular and effective. Anything you cannot measure here, you are deciding by taste, which is fine as long as everyone knows it.

The reason this keeps coming up

Distance to the server is real latency. It is worth being explicit about, because assumptions differ quietly. If it only works because one person remembers to do something, it does not work yet.

A CDN also absorbs traffic spikes. The reasoning matters more than the rule, because the rule has exceptions. Anything you cannot measure here, you are deciding by taste, which is fine as long as everyone knows it.

Where it usually goes wrong

Static sites benefit almost for free. None of that requires a large budget, only a decision and someone to own it. It is the sort of thing that looks like polish right up until it costs you an enquiry.

The short version

Speed is a feature people notice only in its absence, and then they leave rather than complain. Three things worth confirming about a CDN before you move on:

• Someone can say what the current setup is without going to look
• A CDN also absorbs traffic spikes — and you know whether that is true here
• There is a way to tell whether the last change to this helped

Worth checking on your own setup before it becomes someone else's problem to fix.