HTTP status code

This is a list of (HTTP) response status codes. Status codes are issued by a server in response to a browser's request made to the server. It includes codes from IETF Request for Comments (RFCs), other specifications, and some additional codes used in some common applications of the (HTTP). The first digit of the status code specifies one of five standard classes of responses. The message phrases shown are typical, but any human-readable alternative may be provided. Unless otherwise stated, the status code is part of the HTTP/1.1 standard (RFC 7231).

The Internet Assigned Numbers Authority (IANA) maintains the official registry of HTTP status codes.

Microsoft Internet Information Services (IIS) sometimes uses additional decimal sub-codes for more specific information, however these sub-codes only appear in the response payload and in documentation, not in the place of an actual HTTP status code.

An informational response indicates that the request was received and understood. It is issued on a provisional basis while request processing continues. It alerts the client to wait for a final response. The message consists only of the status line and optional header fields, and is terminated by an empty line. As the HTTP/1.0 standard did not define any 1xx status codes, servers must not send a 1xx response to an HTTP/1.0 compliant client except under experimental conditions.

This class of status codes indicates the action requested by the client was received, understood, accepted, and processed successfully.

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.

A user agent may carry out the additional action with no user interaction only if the method used in the second request is GET or HEAD. A user agent may automatically redirect a request. A user agent should detect and intervene to prevent cyclical redirects.

This class of status code is intended for situations in which the error seems to have been caused by the client. Except when responding to a HEAD request, the server should include an entity containing an explanation of the error situation, and whether it is a temporary or permanent condition. These status codes are applicable to any request method. User agents should display any included entity to the user.

The server failed to fulfill a request.

Response status codes beginning with the digit "5" indicate cases in which the server is aware that it has encountered an error or is otherwise incapable of performing the request. Except when responding to a HEAD request, the server should include an entity containing an explanation of the error situation, and indicate whether it is a temporary or permanent condition. Likewise, user agents should display any included entity to the user. These response codes are applicable to any request method.

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