In this blog post we are going to list the error codes and messages that might occur when a web browser makes a request to a web server.
1xx Informational
100 Continue
The request headers have been received by the server. The client should now proceed to send the request body.
101 Switching Protocols
The server is switching to as requested using an Upgrade request header by the client.
103 Checkpoint
Used in the resumable requests proposal aborted PUT or POST requests.
2xx Successful
200 OK
The request has succeeded.
201 Created
The request has been fulfilled and has resulted in one or more new resources being created.
202 Accepted
The request has been accepted for processing but the processing has not been completed
203 Non-Authoritative Information
The server successfully processed the request but is returning information that may be from another source.
204 No Content
The server has successfully fulfilled the request but is not returning any content.
205 Reset Content
The request has been successfully processed but it is not returning any content. Requires the requester to reset the document view.
206 Partial Content
The server is only producing part of the resource due to a range header sent by the client.
3xx Redirection
300 Multiple Choices
The request has more than one possible response. The user should choose one of them.
301 Moved Permanently
The requested page has moved to a new URL.
302 Found
The requested URL has temporarily moved to a new URL.
303 See Other
The requested page can be found under a different URL.
304 Not Modified
The page that has been requested had not been modified since it was last requested.
307 Temporary Redirect
The page has moved to a temporary URL.
308 Resume Incomplete
Used in resumable request proposal to resume an aborted POST or PUT request.
4xx Client Error
400 Bad Request
The server could not understand the request due to invalid syntax.
401 Unauthorised
The request has not been applied because it lacks valid authentication credentials for the target resource.
403 Forbidden
The server understood the request but refuses to authorise it.
404 Not Found
The page requested could not be found.
405 Method Not Allowed
The request method is known by the sever but has been disabled and cannot be used.
406 Not Acceptable
The server can only generate a response that is not accepted by the client.
407 Proxy Authentication Required
The request has not been applied because it lacks valid authentication.
408 Request Timeout
The server has timed out waiting for a response.
409 Conflict
A request conflict with current state of server.
410 Gone
The requested page is no longer available.
411 Length Required
The server refuses to accept the request without a defined content-length header.
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 to large.
414 Request-URI Too long
The URI requested by the client is longer than the server is willing to interpret.
415 Unsupported Media Type
The request has not been accepted by the server as 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 the portion.
417 Exception Failed
The expectation given in the requests Except header could not be met.
5xx Server Error
500 Internal Server Error
Generic error message given when something unexpected happens on the web server and the server can’t offer more specific information.
501 Not Implemented
The request method is not supported by the server and cannot be handled.
502 Bad Gateway
The server, while acting as a gateway or proxy, received an invalid response from the upstream sever.
503 Service Unavailable
The server is currently unavailable.
504 Gateway Timeout
The server did not receive a timely response from an upstream server it accessed to deal with your http request.
505 HTTP Version Not Supported
The server does not support the HTTP protocol version used in the request.
511 Network Authentication Required
The client needs to authenticate to gain network access.