ASP.NET Web API- HTTP Status Codes

HTTP status codes are three-digit numbers that are returned by a server in response to a client's request. They provide information about the status of the request and help in understanding the outcome of the communication between the client and the server.

Here are some common HTTP status codes and their meanings.

S.N.	Code and Description
1	1xx: Informational The server has received the initial part of the request, and the client can proceed with sending the rest of the request.
2	2xx: Success This class of status codes indicates the action requested by the client was received, understood, and accepted.
3	3xx: Redirection This class of status code indicates the client must take additional action to complete the request. Many of these status codes are used in URL redirection.
4	4xx: Client Error This class of status code is intended for situations in which the error seems to have been caused by the client.
5	5xx: Server Error It means the server failed to fulfill an apparently valid request.

HTTP status codes are extensible and HTTP applications are not required to understand the meaning of all the registered status codes. Given below is a list of all the status codes.

1xx: Information

Message	Description
100 Continue	The server has received the initial part of the request, and the client can proceed with sending the rest of the request.

2xx: Successful

Message	Description
200 OK	The request is OK. The request was successful, and the server has returned the requested resource.
201 Created	The request was successful, and a new resource was created as a result.
202 Accepted	The request is accepted for processing, but the processing is not complete.
203 Non-authoritative Information	The information in the entity header is from a local or third-party copy, not from the original server.
204 No Content	The request was successful, but there is no content to return.
205 Reset Content	The browser should clear the form used for this transaction for additional input.
206 Partial Content	The server is returning partial data of the size requested. Used in response to a request specifying a Range header. The server must specify the range included in the response with the Content-Range header.

3xx: Redirection

Message	Description
300 Multiple Choices	A link list. The user can select a link and go to that location. Maximum five addresses.
301 Moved Permanently	The requested resource has been permanently moved to a new URI.
302 Found	The requested resource has been temporarily moved to a different URI.
303 See Other	The client's cached version of the resource is still valid, and there is no need to retrieve it again.
304 Not Modified	This is the response code to an If-Modified-Since or If-None-Match header, where the URL has not been modified since the specified date.
305 Use Proxy	The requested URL must be accessed through the proxy mentioned in the Location header.
306 Unused	This code was used in a previous version. It is no longer used, but the code is reserved.
307 Temporary Redirect	The requested resource is temporarily located at a different URI, and the client should make a new request to that URI.
308 Permanent Redirect	The requested resource is permanently located at a different URI, and the client should make future requests to that URI.

4xx: Client Error

Message	Description
400 Bad Request	The server could not understand the request due to malformed syntax or invalid parameters.
401 Unauthorized	The client needs to authenticate itself to access the requested resource.
402 Payment Required	You can not use this code yet.
403 Forbidden	The server understands the request, but the client does not have access rights to the requested resource.
404 Not Found	The requested resource could not be found on the server.
405 Method Not Allowed	The requested resource does not support the HTTP method used in the request.
406 Not Acceptable	The request cannot be completed due to a conflict with the current state of the resource.
407 Proxy Authentication Required	The client must authenticate itself with the proxy before the requested resource can be accessed.
408 Request Timeout	The request took longer than the server was prepared to wait.
409 Conflict	The request could not be completed because of a conflict.
410 Gone	The requested resource is no longer available and will not be available again.
411 Length Required	The Content-Length is not defined. The server will not accept the request without it .
412 Precondition Failed	The pre condition given in the request evaluated to false by the server.
413 Request Entity Too Large	The server will not accept the request, because the request entity is too large.
414 Request-url Too Long	The server will not accept the request, because the url is too long. Occurs when you convert a "post" request to a "get" request with a long query information .
415 Unsupported Media Type	The server refuses to accept the request because the media type of the request entity is not supported or not compatible with the resource.
416 Requested Range Not Satisfiable	The requested byte range is not available and is out of bounds.
417 Expectation Failed	The expectation given in an Expect request-header field could not be met by this server.

5xx: Server Error

Message	Description
500 Internal Server Error	The request was not completed. The server met an unexpected condition.
501 Not Implemented	The request was not completed. The server did not support the functionality required.
502 Bad Gateway	The server acting as a gateway or proxy received an invalid response from an upstream server.
503 Service Unavailable	The server is currently unable to handle the request due to temporary overload or maintenance
504 Gateway Timeout	The server acting as a gateway or proxy did not receive a timely response from an upstream server.
505 HTTP Version Not Supported	The server does not support the "http protocol" version.