[matte_black]

What if it really is a teapot? Not that farfetched with today's internet connected devices.

[49bc]

I still don't think returning a 418 (in the realm of client errors) is the correct code, even if it is a connected teapot which you're trying to identify!

I think the appropriate action would be a client sends an HTTP HEAD to the service, which responds 200 "TEAPOT".

[hedora]

There’s the EKG+, an internet connected smart kettle:

http://fellowproducts.com/shop/staggekg/

I have the plain EKG, and quite like it.

However, both are designed for pour-over coffee, so can’t correctly return 418.