418 I'm a teapot comes from RFC 2324, the Hyper Text Coffee Pot Control Protocol (HTCPCP), an April Fools' RFC published in 1998. It defined 418 as the answer of a teapot that is asked to brew coffee.
The joke became so popular that many frameworks and libraries implement 418, and some websites return it deliberately, as an easter egg or as a response to unwanted bots. Because of that, RFC 9110 lists 418 as reserved (Unused) in the HTTP status code registry: it is not part of standard HTTP, and it cannot currently be assigned to anything else.
Clients that do not know 418 treat it like 400 Bad Request, as they do with any unknown 4xx code.
Example response
HTTP/1.1 418 I'm a teapot
Date: Fri, 06 Nov 2026 10:15:32 GMT
Content-Type: text/html; charset=utf-8
Content-Length: 100
<!doctype html>
<title>418 I'm a teapot</title>
<p>The requested entity body is short and stout.</p>SEO and redirect checking
Search engines treat 418 like any other 4xx error, so the URL is not indexed. Returning 418 to unwanted bots is effectively a block; make sure the rule does not catch Googlebot or other crawlers you rely on.
Common causes and use cases
- An easter egg page; Google has long served one at
google.com/teapot. - A bot-blocking rule answers scrapers with 418 instead of 403.
- A developer uses 418 as a placeholder or test code.