The Hyper Text Coffee Pot Control Protocol (HTCPCP) is a facetious communication protocol for controlling, monitoring, and diagnosing coffee pots. It is specified in RFC 2324, published on 1 April 1998 as an April Fools' Day RFC, as part of an April Fools prank. An extension, HTCPCP-TEA, was published as RFC 7168 on 1 April 2014 to support brewing teas, which is also an April Fools' Day RFC.
RFC 2324 was written by Larry Masinter, who describes it as a satire, saying "This has a serious purpose – it identifies many of the ways in which HTTP has been extended inappropriately." The wording of the protocol made it clear that it was not entirely serious; for example, it notes that "there is a strong, dark, rich requirement for a protocol designed espressoly [sic] for the brewing of coffee".
Despite the joking nature of its origins, or perhaps because of it, the protocol has remained as a minor presence online. The editor Emacs includes a fully functional client side implementation of it, and a number of bug reports exist complaining about Mozilla's lack of support for the protocol. Ten years after the publication of HTCPCP, the Web-Controlled Coffee Consortium (WC3) published a first draft of "HTCPCP Vocabulary in RDF" in parody of the World Wide Web Consortium's (W3C) "HTTP Vocabulary in RDF".
HTCPCP is an extension of HTTP. HTCPCP requests are identified with the Uniform Resource Identifier (URI) scheme
coffee (or the corresponding word in any other of the 29 listed languages) and contain several additions to the HTTP methods:
||Causes the HTCPCP server to brew coffee. Using POST for this purpose is deprecated. A new HTTP request header field "Accept-Additions" is proposed, supporting optional additions including Cream, Whole-milk, Vanilla, Raspberry, Whisky, Aquavit, etc.|
||"Retrieves" coffee from the HTCPCP server.|
||Returns metadata about the coffee.|
||Says "when", causing the HTCPCP server to stop pouring milk into the coffee (if applicable).|
It also defines two error responses:
||The HTCPCP server is unable to provide the requested addition for some reason; the response should indicate a list of available additions. The RFC observes that "In practice, most automated coffee pots cannot currently provide additions."|
||The HTCPCP server is a teapot; the resulting entity body "may be short and stout" (a reference to the song "I'm a Little Teapot"). Demonstrations of this behaviour exist.|
On 5 August 2017, Mark Nottingham, chairman of the IETF HTTPBIS Working Group, called for the removal of status code 418 "I'm a teapot" from the Node.js platform, a code implemented in reference to the original 418 "I'm a teapot" established in Hyper Text Coffee Pot Control Protocol. On 6 August 2017, Nottingham requested that references to 418 "I'm a teapot" be removed from the programming language Go and subsequently from Python's Requests and ASP.NET's HttpAbstractions library as well.
In response, 15 year old developer Shane Brunswick created a website, save418.com, and established the "Save 418 Movement", asserting that references to 418 "I'm a teapot" in different projects serve as "a reminder that the underlying processes of computers are still made by humans". Brunswick's site went viral in the hours following its publishing, garnering thousands of upvotes on the social platform Reddit, and causing the mass adoption of the "#save418" Twitter hashtag he introduced on his site. Heeding the public outcry, Node.js, Go, Python's Requests, and ASP.NET's HttpAbstractions library decided against removing 418 "I'm a teapot" from their respective projects. The unanimous support from the aforementioned projects and the general public prompted Mark Nottingham to begin the process of having 418 marked as a reserved HTTP status code, ensuring that 418 will not be replaced by an official status code for the foreseeable future.