Common http error status codes

200 -The server successfully returned a web page
404 -The requested web page does not exist
503 -The service is unavailable

Detailed breakdown:

1xx (provisional response)
indicates a status code that temporarily responds and requires the requester to continue the operation.

Code description

100 (Continued) The requester shall continue to make requests. The server returns this code to indicate that it has received the first part of the request and is waiting for the rest.
101 (switching protocol) The requester has requested the server to switch the protocol, and the server has confirmed and is ready to switch.

2xx (success)
indicates that the status code of the request was successfully processed.

Code description *** 200 *** (Successful) The server has successfully processed the request. Usually, this means that the server provided the requested web page. *** 201 *** (Created) The request was successful and the server created a new resource. *** 202 *** (Accepted) The server has accepted the request, but has not yet processed it. *** 203 *** (Unauthorized information) The server has successfully processed the request, but the information returned may come from another source. *** 204 *** (No content) The server successfully processed the request but returned nothing. *** 205 *** (Reset content) The server successfully processed the request but returned nothing. *** 206 *** (Partial content) The server successfully processed part of the GET request.

3xx (Redirect)
indicates that further action is required to complete the request. Usually, these status codes are used for redirection.

Code description
300 (multiple choices) The server can perform various operations in response to requests. The server can select an operation according to the requester (user agent), or provide a list of operations for the requester to choose.
301 (Permanently Moved) The requested webpage has been permanently moved to a new location. When the server returns this response (in response to a GET or HEAD request), it automatically transfers the requester to the new location.
302 (Temporary Mobile) The server is currently responding to requests from web pages in different locations, but the requester should continue to use the original location for future requests.
303 (see other locations) When the requester should use a separate GET request to retrieve the response for different locations, the server returns this code.
304 (Unmodified) Since the last request, the requested webpage has not been modified. When the server returns this response, it will not return the content of the web page.
305 (Use proxy) The requester can only use the proxy to access the requested web page. If the server returns this response, it also indicates that the requester should use a proxy.
307 (Temporary redirect) The server currently responds to requests from web pages in different locations, but the requester should continue to use the original location for future requests.

4xx (Request error)
These status codes indicate that the request may be in error, which prevents the server from processing.

Code description
400 (Bad request) The server does not understand the syntax of the request.
401 (Unauthorized) The request requires authentication. For web pages that require login, the server may return this response.
403 (Forbidden) The server rejected the request.
404 (Not Found) The server cannot find the requested page.
405 (Method disabled) Disable the method specified in the request.
406 (Not accepted) Unable to respond to the requested webpage with the requested content characteristics.
407 (agent authorization required) This status code is similar to 401 (unauthorized), but specifies that the requestor should authorize the use of an agent.
408 (Request timeout) The server timed out while waiting for the request.
409 (Conflict) The server encountered a conflict while completing the request. The server must include information about the conflict in the response.
410 (Deleted) If the requested resource has been permanently deleted, the server will return this response.
411 (requires effective length) The server does not accept requests without the effective content length header field.
412 (Prerequisite not met) The server did not meet one of the prerequisites set by the requester in the request.
413 (The request entity is too large) The server cannot process the request because the request entity is too large and exceeds the processing capacity of the server.
414 (Requested URI is too long) The requested URI (usually a URL) is too long for the server to process.
415 (Unsupported media type) The requested format is not supported by the requested page.
416 (The requested range does not meet the requirements) If the page cannot provide the requested range, the server returns this status code.
417 (Expectations not met) The server did not meet the requirements of the "Expectations" request header field.

5xx (Server Error)
These status codes indicate that the server encountered an internal error while trying to process the request. These errors may be the server's own error, rather than the request error.

Code description
500 (Internal server error) The server encountered an error and could not complete the request.
501 (Not yet implemented) The server does not have the function to complete the request. For example, this code may be returned when the server does not recognize the request method.
502 (Bad gateway) The server acting as a gateway or proxy received an invalid response from the upstream server.
503 (Service unavailable) The server is currently unavailable (due to overload or downtime maintenance). Usually, this is only a temporary state.
504 (Gateway timeout) The server acts as a gateway or proxy, but did not receive the request from the upstream server in time.
505 (HTTP version is not supported) The server does not support the HTTP protocol version used in the request.