HTTP 418 — I'm a teapot
The server refuses to brew coffee because it is a teapot
When to use it
Use status 418 when this is the correct HTTP response semantic: The server refuses to brew coffee because it is a teapot
Request and response example
GET /protected-resource HTTP/1.1
Host: api.example.com
HTTP/1.1 418 I'm a teapot
Content-Type: application/json
{"error":"Request cannot be completed"}