TechNote (Archived)

HTTP protocol codes

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HTTP (Hypertext Transfer Protocol Version 1.x ) Server Response

HTTP is the protocol that allows web servers and browsers to exchange data over the web. It is a request/response protocol, meaning the server waits for and responds to client requests. HTTP does not maintain a connection with the client. These client/server transactions can be divided into four basic steps:

The browser connects to the server.
The browser requests a document from the server.
The server responds to the browser.
The connection is dropped.

HTTP is a stateless protocol in that it does not maintain any information about the connections.

If a web developer is operating a web server or web application, it is recommended to obtain reference or troubleshooting information that is specific to the web server application software. This can assist with resolving HTTP errors that are specific to web server software itself or applications that are interacting with the web server.

HTTP/1.1 is the current standard. It is described in RFC 2616, which can be found at the W3C's Hypertext Transfer Protocol Version 1.x site.

Groups of status codes

Informational	The codes between 100 and 199 are Informational response codes. They are only implemented under HTTP version 1.1. They indicate that the request from the browser has been received and is being processed.
Successful	Server response codes between 200 and 299 indicate that the client's request was successful. The request was received, understood, and processed.
Redirection	A response code in the range of 300 to 399 indicates that the client's request was not fulfilled, and further action must be taken on the part of the client to successfully complete the request. For example, if the requested page has moved, a Redirection response code is sent to tell the client that it needs to request the page again from the new location.
Client Error	Response codes between 400 and 499 indicate that there is some error in the client's request. These errors can indicate that the page was not found, that the client's request used invalid syntax, or that access to the page was denied.
Server Error	A response code in the range of 500 to 599 indicates that there is a problem with the server that prevents it from fulfilling the request. Usually information is sent along with this response code that elaborates on the problem.

Status codes and description phrases

100 Continue
101 Switching protocols
200 OK
201 Created
202 Accepted
203 Non-authoritative information
204 No content
205 Reset content
206 Partial content
300 Multiple choices
301 Moved permanently
302 Moved temporarily
303 See other
304 Not modified
305 Use proxy
400 Bad request
401 Unauthorized
402 Payment required
403 Forbidden
404 Not found
405 Method not allowed
406 Not acceptable
407 Proxy authentication required
408 Request timeout
409 Conflict
410 Gone
411 Length required
412 Precondition failed
413 Request entity too large
414 Request-URI too long
415 Unsupported media type
500 Internal server error
501 Not implemented
502 Bad gateway
503 Service unavailable
504 Gateway timeout
505 HTTP version not supported