HTTP 상태 코드

1xx  정보 — 요청을 받았고 처리가 이어짐
2xx  성공 — 잘 됐음
3xx  리다이렉트 — 다른 곳을 볼 것
4xx  요청 오류 — 대개 클라이언트가 고칠 수 있음
5xx  서버 오류 — 클라이언트는 다시 시도할 수밖에 없음

100  Continue (계속)
     Carry on sending the body; the headers were acceptable.
101  Switching Protocols (프로토콜 전환)
     Agreed — usually the handshake into a WebSocket.
200  OK (성공)
     It worked, and the body is the answer.
201  Created (생성됨)
     It worked and something new exists; Location says where.
202  Accepted (접수됨)
     Taken in, not done yet. Nothing promises it will succeed.
204  No Content (내용 없음)
     It worked and there is deliberately nothing to send back.
206  Partial Content (부분 내용)
     Here is the range you asked for — how video seeking works.
301  Moved Permanently (영구 이동)
     Use the new address from now on; search engines move their index.
302  Found (임시로 다른 곳에 있음)
     Temporarily elsewhere. Keep using this address.
303  See Other (다른 주소 참조)
     Done — now GET that other address. The answer to a form POST.
304  Not Modified (변경 없음)
     Your copy is current; nothing is sent. The point of caching.
307  Temporary Redirect (임시 리다이렉트)
     Like 302 but the method must not change.
308  Permanent Redirect (영구 리다이렉트)
     Like 301 but the method must not change.
400  Bad Request (잘못된 요청)
     The request itself is malformed. Not the same as invalid data.
401  Unauthorized (인증되지 않음)
     Not authenticated. Misnamed: it means “who are you?”.
402  Payment Required (결제 필요)
     Reserved for years, now used by some APIs for quota and billing.
403  Forbidden (금지됨)
     Authenticated and still not allowed. “I know who you are; no.”
404  Not Found (찾을 수 없음)
     Nothing here, and nothing said about whether there ever was.
405  Method Not Allowed (허용되지 않은 메서드)
     The address exists; that verb does not work on it.
406  Not Acceptable (받아들일 수 없음)
     Nothing can be produced that matches the Accept header.
408  Request Timeout (요청 시간 초과)
     The client took too long to send it.
409  Conflict (충돌)
     It clashes with the current state — an edit against a stale version.
410  Gone (삭제됨)
     It was here and is deliberately gone. Stronger than 404.
413  Payload Too Large (요청이 너무 큼)
     The body is bigger than the server will take.
415  Unsupported Media Type (지원하지 않는 미디어 유형)
     The Content-Type is not one this endpoint reads.
418  I'm a teapot (나는 찻주전자)
     A 1998 April Fools joke, in the standard, still implemented for fun.
422  Unprocessable Content (처리할 수 없는 내용)
     Well formed, but the data fails validation. The one people want when they reach for 400.
425  Too Early (너무 이름)
     Refusing a replayable request sent in TLS early data.
428  Precondition Required (전제 조건 필요)
     Send an If-Match so you do not overwrite somebody blindly.
429  Too Many Requests (요청이 너무 많음)
     Rate limited. Retry-After says how long to wait.
431  Request Header Fields Too Large (헤더가 너무 큼)
     Usually one enormous cookie.
451  Unavailable For Legal Reasons (법적인 이유로 이용 불가)
     Blocked by law. The number is a Fahrenheit 451 joke.
500  Internal Server Error (서버 내부 오류)
     Something threw. The catch-all, and a sign nothing more specific was chosen.
501  Not Implemented (구현되지 않음)
     The server does not support that method at all.
502  Bad Gateway (잘못된 게이트웨이)
     A proxy got nonsense from upstream. Usually the app behind it is down.
503  Service Unavailable (서비스 이용 불가)
     Temporarily down or overloaded; Retry-After may say when.
504  Gateway Timeout (게이트웨이 시간 초과)
     A proxy waited for upstream and gave up.
507  Insufficient Storage (저장 공간 부족)
     No room to hold what was sent.