What does HTTP status code 418 mean?
HTTP status code 418 is reserved and has no defined meaning in HTTP. It began as “I’m a teapot”, part of the Hyper Text Coffee Pot Control Protocol in RFC 2324, an April 1 RFC that lampooned ways HTTP was abused. The joke was deployed often enough that RFC 9110 (Section 15.5.19) marks 418 as “(Unused)” and reserves it in the IANA registry, so it cannot be assigned to another use for now.
When to use it in APIs
Never. It has no semantics in HTTP, so no client can act on it. If you want an easter egg, keep it out of any endpoint a real client calls.
How it compares to other codes
- 400 Bad Request: Standard error representation for real client issues.
