Many, many users, but your server is waiting 🕙 for their not-so-good connection to send their requests.

And then waiting 🕙 again for the responses to come back.

This "waiting" 🕙 is measured in microseconds, but still, summing it all, it's a lot of waiting in the end.

That's why it makes a lot of sense to use asynchronous ⏸🔀⏯ code for web APIs.

You could put an **arbitrary number** to target, for example, something **between 50% to 90%** of resource utilization. The point is that those are probably the main things you will want to measure and use to tweak your deployments.