HTTP Status Codes

When a client (browser) requests a page from a web server, various status codes are included in the messages that are sent back and forth. These messages can be used to help troubleshoot issues preventing web pages from properly being delivered to the browser.

Some browsers are configured by default to not show these messages, but rather show a friendly form of the status code. Generally, you can disable the friendly messages in the advanced configuration of the browser. Here is a list of status codes that may be exchanged.

1xx Information

Status Code	Description
`100 Continue`	This interim response is used to inform the client that the initial part of the request has been received.
`101 Switching Protocols`	The requester has asked the server to switch protocols.

2xx: Successful

Status Code	Description
`200 OK`	The request has succeeded.
`201 Created`	The request has been fulfilled and resulted in a new resource being created.
`202 Accepted`	The request has been accepted for processing, but the processing has not been completed.
`203 Non-Authoritative Information`	The request has been fulfilled but is returning information that may be from another source.
`204 No Content`	The request has been successfully fulfilled but is not returning any content.
`205 Reset Content`	The request has been successfully fulfilled but s not returning any content.
`206 Partial Content`	The server is delivering only part of the resource due to a range header sent by the client.

3xx: Redirection

Status Code	Description
`300 Multiple Choices`	The user can select a link and go to that location. Max of five addresses.
`301 Moved Permanently`	The requested page has moved to a new URI.
`302 Found`	The requested page has moved temporarily to a new URI.
`303 See Other`	The requested page can be found under a different URI.
`304 Not Modified`	Indicates the requested page has not been modified since last requested.
`305 Use Proxy`	The requested resource must be accessed through the proxy given by the Location field.
`307 Temporary Redirect`	The requested page has moved temporarily to a new URI.
`308 Resume Incomplete`	Used in the resumable requests proposal to resume aborted PUT or POST requests.

4xx: Client Error

Status Code	Description
`400 Bad Request`	The request cannot be fulfilled due to malformed syntax.
`401 Unauthorized`	The request requires user authentication.
`402 Payment Required`	Reserved for future use.
`403 Forbidden`	The server understood the request but is refusing to fulfill it.
`404 Not Found`	The server has not found anything matching the Request-URI.
`405 Method Not Allowed`	The method specified in the Request-Line is not allowed for the resource.
`406 Not Acceptable`	The server can only generate a response that is not accepted by the client.
`407 Proxy Authentication Required`	The client must first authenticate itself with the proxy.
`408 Request Timeout`	The server timed out waiting for the request.
`409 Conflict`	The request could not be completed because of a conflict in the request.
`410 Gone`	The requested page is no longer available and no forwarding address is known.
`411 Length Required`	The server refuses to accept the request without a defined Content-Length.
`412 Precondition Failed`	The precondition 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-URI Too Long`	The server will not accept the request, because the URI is too long.
`415 Unsupported Media Type`	The server will not accept the request, because the media type is not supported.
`416 Requested Range Not Satisfiable`	The client has asked for a portion of the file, but the server cannot supply that portion.
`417 Expectation Failed`	The server cannot meet the requirements of the Expect request-header field.

5xx: Server Error

Status Code	Description
`500 Internal Server Error`	The server encountered an unexpected condition that prevented it from fulfilling the request.
`501 Not Implemented`	The server does not support the functionality required to fulfill the request.
`502 Bad Gateway`	The server was acting as a proxy and received an invalid response from the upstream server.
`503 Service Unavailable`	The server is currently unable to handle the request due to temporary overloading or maintenance.
`504 Gateway Timeout`	The server was acting as a proxy or and did not receive a timely response from the upstream server.
`505 HTTP Version Not Supported`	The server does not support the HTTP protocol version that was used in the request message.