"You could argue that I’m abusing 414 URI Too Long. I respond that it’s funnier this way. Other options I considered were:

    400 Bad Request, the generic client error code, which is correct but boring;

    402 Payment Required, and honestly if you want to pay me to make a particular URL with query string work, I’m open to it;

    404 Not Found, but it’s too likely to have side effects, and it doesn’t convey the idea that the request was malformed, which is what I’m going for; and

    303 See Other with no Location header, which is extremely uncommon these days but legitimate. Or at least it was in RFC 2616 (“The different URI SHOULD be given by the Location field in the response”), but it was reworded in 7231 and 9110 in a way that assumes the presence of a Location header (“… as indicated by a URI in the Location header field”), while 301, 302, 307 and 308 say “the server SHOULD generate a Location header field”. Well, I reckon See Other with no Location header is fair enough. But URI Too Long was funnier."