HTTP 상태 코드

1xx  informational — the request was received and work continues
2xx  success — it worked
3xx  redirection — look somewhere else
4xx  the request is wrong — the client can usually fix it
5xx  the server is wrong — the client can only retry

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