The following is a list of HyperText Transfer Protocol (HTTP) response status codes. This includes codes from IETF internet standards as well as unstandardised RFCs, other specifications and some additional commonly used codes. The first digit of the status code specifies one of five classes of response; the bare minimum for an HTTP client is that it recognises these five classes. Microsoft IIS may use additional decimal sub-codes to provide more specific information, but these are not listed here. The phrases used are the standard examples, but any human-readable alternative can be provided. Unless otherwise stated, the status code is part of the HTTP/1.1 standard.
Request received, continuing process.
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. Since HTTP/1.0 did not define any 1xx status codes, servers must not send a 1xx response to an HTTP/1.0 client except under experimental conditions.
This means that the server has received the request headers, and that the client should proceed to send the request body (in the case of a request for which a body needs to be sent; for example, a POST request). If the request body is large, sending it to a server when a request has already been rejected based upon inappropriate headers is inefficient. To have a server check if the request could be accepted based on the request's headers alone, a client must send Expect: 100-continue as a header in its initial request and check if a 100 Continue status code is received in response before continuing (or receive 417 Expectation Failed and not continue).
101 Switching Protocols
102 Processing (WebDAV)
The action was successfully received, understood, and accepted.
This class of status code indicates that the client's request was successfully received, understood, and accepted.
Standard response for successful HTTP requests. The actual response will depend on the request method used. In a GET request, the response will contain an entity corresponding to the requested resource. In a POST request the response will contain an entity describing or containing the result of the action.
The request has been fulfilled and resulted in a new resource being created.
The request has been accepted for processing, but the processing has not been completed. The request might or might not eventually be acted upon, as it might be disallowed when processing actually takes place.
203 Non-Authoritative Information (since HTTP/1.1)
204 No Content
205 Reset Content
206 Partial Content
The server is serving only part of the resource due to a range header sent by the client. This is used by tools like wget to enable resuming of interrupted downloads, or split a download into multiple simultaneous streams.
207 Multi-Status (WebDAV)
The message body that follows is an XML message and can contain a number of separate response codes, depending on how many sub-requests were made.
The client must take additional action to complete the request.
This class of status code indicates that further action needs to be taken by the user agent in order to fulfil the request. The action required may be carried out by the user agent without interaction with the user if and only if the method used in the second request is GET or HEAD. A user agent should not automatically redirect a request more than five times, since such redirections usually indicate an infinite loop.
300 Multiple Choices
Indicates multiple options for the resource that the client may follow. It, for instance, could be used to present different format options for video, list files with different extensions, or word sense disambiguation.
301 Moved Permanently
This and all future requests should be directed to the given URI.
This is the most popular redirect code, but also an example of industrial practice contradicting the standard. HTTP/1.0 specification (RFC 1945) required the client to perform a temporary redirect (the original describing phrase was "Moved Temporarily"), but popular browsers implemented it as a 303 See Other. Therefore, HTTP/1.1 added status codes 303 and 307 to disambiguate between the two behaviours. However, the majority of Web applications and frameworks still use the 302 status code as if it were the 303.
303 See Other (since HTTP/1.1)
The response to the request can be found under another URI using a GET method. When received in response to a PUT, it should be assumed that the server has received the data and the redirect should be issued with a separate GET message.
304 Not Modified
Indicates the resource has not been modified since last requested. Typically, the HTTP client provides a header like the If-Modified-Since header to provide a time against which to compare. Utilizing this saves bandwidth and reprocessing on both the server and client.
305 Use Proxy (since HTTP/1.1)
Many HTTP clients (such as Mozilla and Internet Explorer) do not correctly handle responses with this status code, primarily for security reasons.
306 Switch Proxy
No longer used.
307 Temporary Redirect (since HTTP/1.1)
In this occasion, the request should be repeated with another URI, but future requests can still use the original URI. In contrast to 303, the request method should not be changed when reissuing the original request. For instance, a POST request must be repeated using another POST request.
4xx Client Error:
The request contains bad syntax or cannot be fulfilled.
The 4xx class of status code is intended for cases in which the client seems to have erred. 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. These are typically the most common error codes encountered while online.
400 Bad Request
The request contains bad syntax or cannot be fulfilled.
Similar to 403 Forbidden, but specifically for use when authentication is possible but has failed or not yet been provided. See Basic access authentication and Digest access authentication.
402 Payment Required
The original intention was that this code might be used as part of some form of digital cash or micropayment scheme, but that has not happened, and this code has never been used.
The request was a legal request, but the server is refusing to respond to it. Unlike a 401 Unauthorized response, authenticating will make no difference.
404 Not Found
The requested resource could not be found but may be available again in the future. Subsequent requests by the client are permissible.
405 Method Not Allowed
A request was made of a resource using a request method not supported by that resource; for example, using GET on a form which requires data to be presented via POST, or using PUT on a read-only resource.
406 Not Acceptable
The requested resource is only capable of generating content not acceptable according to the Accept headers sent in the request.
407 Proxy Authentication Required
408 Request Timeout
Client failed to continue the request
Indicates that the request could not be processed because of conflict in the request, such as an edit conflict.
Indicates that the resource requested is no longer available and will not be available again. This should be used when a resource has been intentionally removed; however, it is not necessary to return this code and a 404 Not Found can be issued instead. Upon receiving a 410 status code, the client should not request the resource again in the future. Clients such as search engines should remove the resource from their indexes.
411 Length Required
The request did not specify the length of its content, which is required by the requested resource.
412 Precondition Failed
413 Request Entity Too Large
The resource that was requested is too large to transmit using the current protocol.
414 Request-URI Too Long
The URI provided was too long for the server to process.
415 Unsupported Media Type
The request did not specify any media types that the server or resource supports. For example the client specified that an image resource should be served as image/svg+xml, but the server cannot find a matching version of the image.
416 Requested Range Not Satisfiable
The client has asked for a portion of the file, but the server cannot supply that portion (for example, if the client asked for a part of the file that lies beyond the end of the file).
417 Expectation Failed
418 I'm a teapot
The HTCPCP server is a teapot. The responding entity MAY be short and stout. Defined by the April Fools' specification RFC 2324. See Hyper Text Coffee Pot Control Protocol for more information.
422 Unprocessable Entity (WebDAV) (RFC 4918)
The request was well-formed but was unable to be followed due to semantic errors.
423 Locked (WebDAV) (RFC 4918)
The resource that is being accessed is locked
424 Failed Dependency (WebDAV) (RFC 4918)
The request failed due to failure of a previous request (e.g. a PROPPATCH).
425 Unordered Collection
Defined in drafts of WebDav Advanced Collections, but not present in "Web Distributed Authoring and Versioning (WebDAV) Ordered Collections Protocol" (RFC 3648).
426 Upgrade Required (RFC 2817)
The client should switch to TLS/1.0.
449 Retry With
A Microsoft extension. The request should be retried after doing the appropriate action.
A Microsoft extension. Used for blocking sites with Windows Parental Controls.
5xx Server Error:
The server failed to fulfil an apparently valid 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.
500 Internal Server Error
A generic error message, given when no more specific message is suitable.
501 Not Implemented
The server either does not recognise the request method, or it lacks the ability to fulfil the request.
502 Bad Gateway
503 Service Unavailable
504 Gateway Timeout
505 HTTP Version Not Supported
506 Variant Also Negotiates (RFC 2295)
507 Insufficient Storage (WebDAV) (RFC 4918)
509 Bandwidth Limit Exceeded (Apache bw/limited extension)
This status code, while used by many servers, is not specified in any RFCs.
510 Not Extended (RFC 2774)
Further extensions to the request are required for the server to fulfil it.