[simonw]

Right: in this day and age there are an almost unlimited array of inexpensive, easy ways to spin up an HTTP endpoint that can receive a POST request.

We have a lot of experience scaling those kinds of endpoints (and making them redundant) too.

Spinning up an always-on server that can maintain a persistent connection - and reconnect automatically if it drops, and if the server is rebooted with an update and suchlike - is a whole lot harder. Possible, but not nearly as easy.