100 :- Continue
101 :- Switching Protocols
102 :- Processing (WebDAV; RFC 2518)
200 :- OK
201 :- Created
202 :- Accepted
203 :- Non-Authoritative Information (since HTTP/1.1)
204 :- No Content
205 :- Reset Content
206 :- Partial Content
207 :- Multi-Status (WebDAV; RFC 4918)
208 :- Already Reported (WebDAV; RFC 5842)
226 :- IM Used (RFC 3229)
300 :- Multiple Choices
301 :- Moved Permanently
302 :- Found
303 :- See Other (since HTTP/1.1)
304 :- Not Modified
305 :- Use Proxy (since HTTP/1.1)
306 :- Switch Proxy
307 :- Temporary Redirect (since HTTP/1.1)
308 :- Permanent Redirect (approved as experimental RFC)[12]
400 :- Bad Request
401 :- Unauthorized
402 :- Payment Required
403 :- Forbidden
404 :- Not Found
405 :- Method Not Allowed
406 :- Not Acceptable
407 :- Proxy Authentication Required
408 :- Request Timeout
409 :- Conflict
410 :- Gone
411 :- Length Required
412 :- Precondition Failed
413 :- Request Entity Too Large
414 :- Request-URI Too Long
415 :- Unsupported Media Type
416 :- Requested Range Not Satisfiable
417 :- Expectation Failed
418 :- I'm a teapot (RFC 2324)
419 :- Authentication Timeout (not in RFC 2616)
420 :- Method Failure (Spring Framework)
420 :- Enhance Your Calm (Twitter)
422 :- Unprocessable Entity (WebDAV; RFC 4918)
423 :- Locked (WebDAV; RFC 4918)
424 :- Failed Dependency (WebDAV; RFC 4918)
424 :- Method Failure (WebDAV)[14]
425 :- Unordered Collection (Internet draft)
426 :- Upgrade Required (RFC 2817)
428 :- Precondition Required (RFC 6585)
429 :- Too Many Requests (RFC 6585)
431 :- Request Header Fields Too Large (RFC 6585)
440 :- Login Timeout
444 :- No Response (Nginx)
449 :- Retry With (Microsoft)
450 :- Blocked by Windows Parental Controls (Microsoft)
451 :- Unavailable For Legal Reasons (Internet draft)
451 :- Redirect (Microsoft)
494 :- Request Header Too Large (Nginx)
495 :- Cert Error (Nginx)
496 :- No Cert (Nginx)
497 :- HTTP to HTTPS (Nginx)
499 :- Client Closed Request (Nginx)
500 :- Internal Server Error
501 :- Not Implemented
502 :- Bad Gateway
503 :- Service Unavailable
504 :- Gateway Timeout
505 :- HTTP Version Not Supported
506 :- Variant Also Negotiates (RFC 2295)
507 :- Insufficient Storage (WebDAV; RFC 4918)
508 :- Loop Detected (WebDAV; RFC 5842)
509 :- Bandwidth Limit Exceeded (Apache bw/limited extension)
510 :- Not Extended (RFC 2774)
511 :- Network Authentication Required (RFC 6585)
522 :- Connection timed out
524 :- A timeout occurred
598 :- Network read timeout error (Unknown)
599 :- Network connect timeout error (Unknown)