There exists an official RFC protocol purely for interacting with a coffee machine over the wire. Think about that for a second: there must have been enough internet capable coffee machines, possibly with differing protocols, such that a standardising process was necessary.

It uses HTTP/1.1 to send BREW commands. The URI scheme is “coffee:”. You cannot make this stuff up.

Here’s the spec in case your interested in making your own client/server system using it.