Every request we issue to the server, the server parses it and build the response to return the result to the client. As Web API is REST service, every response is represented with a state, a HTTP status should be semantically used to inform the client with result.
There are five types of HTTP status codes:
- Informational (1xx)
- Success (2xx)
- Redirection (3xx)
- Client errors (4xx)
- Server errors (5xx)
Every Group has its own details. For e.g., if during request all thing goes well, after GET request the status code of the response is 200 OK , but after a POST request is 201 CREATED.
This class of status code indicates a provisional response, consisting only of the Status-Line and optional headers, and is terminated by an empty line. In this group, there are two status code:
- 100 – Continue
- 101 – Switching Protocols
This class of status code indicates that the client’s request was successfully received, processed, and accepted. In this group, there are seven status code:
This status code indicate request has succeeded.
This status code tells the request has been processed and resulted in a new resources being created. The newly created resource can be referenced by the URI return in the responses header field.
This status code tells the request has been accepted for processing, but processing has not been completed.
203 Non-Authoritative Information
This status code tells that returned meta information in response header is not definitive set as available from the origin server, but gathered from a local or third party copy.
204 No Content
This status code tells that the server has processed the request but does not need to return a response, and might want to return updated meta information.
205 Reset Content
This status code tells that the server has processed the request and the user agent SHOULD reset the document view which caused the request to be sent.
206 Partial Content
This status code tells that the server has processed the partial GET request for the resource.
This group of status code indicates that further action needs to be taken by the user agent in order to fulfil the request. In this group, there are eight status code:
300 Multiple Choices
If the requested resource having a set of representations, each with its own specific location, and agent-driven negotiation information is being provided so that the user can select a preferred representation and redirect its request to that location.
301 Moved Permanently
This status code indicate that the requested resource has been assigned a new permanent URI and any future references to this resource SHOULD use one of the returned URIs.
This status code indicates that the requested resource resides temporarily under a different URI.
303 See Other
This status code indicates that the response to the request can be found under a different URI and SHOULD be retrieved using a GET method on that resource.
304 Not Modified
This status code indicates that if the client has performed a conditional GET request and access is allowed, but the document has not been modified, the server SHOULD respond with this status code.
305 Use Proxy
This status code indicates that the requested resource MUST be accessed through the proxy given by the Location field. The Location field gives the URI of the proxy.
The 306 status code was used in a previous version of the specification, is no longer used, and the code is reserved.
307 Temporary Redirect
This status code indicates that the requested resource resides temporarily under a different URI. Since the redirection may be altered on occasion, the client should continue to use the Request-URI for future requests.
Client Error 4xx
The 4xx group of status code is indicates that the client seems to have erred. In this group, there are 18 status code:
400 Bad Request
This code indicates that the request could not be understood by the server due to syntax error in request. The client should not repeat the request without modifications.
This code indicates that the request requires user authentication. The response must include a WWW-Authenticate header field to the requested resource.
402 Payment Required
This code is reserved for future use.
This code indicates that the server understood the request, but is refusing to process it. Authorization will not help in this case and the request should not be repeated.
404 Not Found
This code indicates that the server has not found anything matching the Request-URI.
405 Method Not Allowed
This code indicates that the method specified in the Request-Line is not allowed for the resource identified by the Request-URI.
406 Not Acceptable
This code indicates that the resource identified by the request is only capable of generating response entities which have content characteristics not acceptable according to the accept headers sent in the request.
407 Proxy Authentication Required
This code is similar to 401 (Unauthorized), but indicates that the client must first authenticate itself with the proxy.
408 Request Timeout
This code indicates that the client did not produce a request within the time that the server was prepared to wait.
This code indicates that the request could not be completed due to a conflict with the current state of the resource. This code is should only used in situations where it is expected that the user might be able to resolve the conflict and resubmit the request.
This code indicates that the requested resource is no longer available at the server and no forwarding address is known.
411 Length Required
This code indicates that the server refuses to accept the request without a defined Content-Length.
412 Precondition Failed
This code indicates that one or more of the request-header fields evaluated to false when it was tested on the server.
413 Request Entity Too Large
This code indicates that the server is refusing to process a request because the request entity is larger than the server is willing or able to process.
414 Request-URI Too Long
This code indicates that the server is refusing to service the request because the Request-URI is longer than the server is willing to interpret.
415 Unsupported Media Type
This code indicates that the server is refusing to service the request because the entity of the request is in a format not supported by the requested resource for the requested method.
416 Requested Range Not Satisfiable
417 Expectation Failed
Server Error 5xx
The 5xx group of status code is indicates cases in which the server is aware that it has erred or is incapable of performing the request.
500 Internal Server Error
This code indicates that the server encountered an unexpected condition which prevented it from processing the request.
501 Not Implemented
This code indicates that the server does not support the functionality required to process the request. This is the appropriate response when the server does not recognize the request method and is not capable of supporting it for any resource.
502 Bad Gateway
This code indicates that the server, while acting as a gateway or proxy, received an invalid response from the upstream server it accessed in attempting to process the request.
503 Service Unavailable
This code indicates that the server is currently unable to handle the request due to a temporary overloading or maintenance of the server.
504 Gateway Timeout
This code indicates that the server, while acting as a gateway or proxy, did not receive a timely response from the upstream server specified by the URI or some other auxiliary server (e.g., DNS) it needed to access in attempting to complete the request.
505 HTTP Version Not Supported
This code indicates that the server does not support, or refuses to support, the HTTP protocol version that was used in the request message.
I hope that you will have better understanding of which HTTP status code should be used in API response. I would like to hear valuable feedback or question from you. It encourage me to write more quality article.
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