Type localhost and you are talking to your own machine. Type mylocalhost.com and you are talking to a real server on the public internet — which is the problem, and now the point.
The name turns up in example code, in half-finished config files, in tutorials, in default values that were never meant to ship. Somewhere between a developer writing a placeholder and that placeholder reaching production, requests start arriving here: webhooks, health checks, login attempts, uploads. Requests meant for someone's laptop, sent to a stranger's server.
None of it is answered with anything useful, and none of it is kept beyond half an hour — only the count survives. But it made the shape of the thing obvious: this is a domain people already send HTTP requests to by accident. So it may as well be a domain you can send HTTP requests to on purpose, and read what you sent.
A temporary HTTP endpoint and an inspector. Click once, get a URL, send anything to it, and see the request exactly as it arrived. No account, no cost, nothing kept beyond thirty minutes.
Roughly in this order, and only if the step before it gets used.
It is a memorable name with real inbound traffic, and people do ask about it. If you want to talk about partnering, building on it or buying it — hello@mylocalhost.com.