HTTP 418 (Unused)

Client error code, RFC 9110, section 15.5.19

What it means

In RFC 9110 this number is reserved and "unused". The "I'm a teapot" answer comes from an April Fools' RFC from 1998 about controlling coffee pots.

A real response

This is the request and the answer our test server gave when we asked it to return 418.

GET /c/418 HTTP/1.1
Host: example.com

HTTP/1.1 418 I'm a Teapot
Date: Sat, 14 Nov 2026 10:00:00 GMT
Content-Type: text/html; charset=utf-8
Content-Length: 11

<p>demo</p>

If you run the site

Do not use 418 for anything serious. Some sites send it on purpose for blocked bots, which is a convention and not part of the standard. If you see it from a site that is not joking, it usually means a security system blocked the request.

If you are a visitor

If it appears on a normal site, a bot or security filter probably rejected the request. Try again later without a VPN.

A common mistake

Treating 418 as a real standard code in a program.

Registered in the IANA HTTP Status Code Registry as (Unused), defined in RFC 9110, section 15.5.19.

This is an independent guide. It is not connected with the IETF, IANA, any browser maker or any company named here. Meanings were checked against the RFC texts on 14 November 2026. Responses shown were recorded on 14 November 2026 from a small test server on the author's own computer.