Introduction to HTTP Status Response Codes

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Before going into the detailed description of each status codes we need to understand some definitions which are necessary to fully understand the terms used in this context.

What is Hypertext Transfer Protocol (HTTP)?

HTTP is a stateless protocol means (the request which client generated must have some response from server and no data reside on server while processing both). Http Follow client-server approach as client send request from browser and in return server response. For every request you send to server you have to wait for response that browser shows in the form or HTML.

HTTP consist of Headers, Cookies, DNS Prefetching, Response Codes, Request Methods and Access Authentication.

We Will discuss in detail about the main backbones of HTTP Request-Response Model.

There are several versions of HTTP, but currently HTTP 1.1 is in use.

Hope you understand the basics of HTTP, Now Let's start with the key area of HTTP Request - Response Model which is Http Response Codes.

HTTP Response Codes

These provide information about certain HTTP Requests either they are completed or not.

These are 3 digit codes.

These are grouped in to five major categories enlisted below:

Status Code Group	Status Info	Status Description
1xx	Informational	Continue and processing.
2xx	Success	Response Successful, no action required, Ok Status
3xx	Redirection	Need more action to fulfill the request.
4xx	Client Error	The Request contains unknown syntax and server did not fulfill the request.
5xx	Server Error	The Server failed to fulfill the valid request.

List of Common HTTP Status Response Codes

200 OK
300 Multiple Choices
301 Moved Permanently
302 Found
304 Not Modified
307 Temporary Redirect
400 Bad Request
401 Unauthorized
403 Forbidden
404 Not Found
410 Gone
500 Internal Server Error
501 Not Implemented
503 Service Unavailable
550 Permission denied

Code and Description of Other Response Codes

1xx Informational Responses

HTTP status codes in the 1xx are typically informational.

100 Continue
101 Switching Protocols
102 Processing
103 Checkpoint
122 Request-URI too long

2xx Successful Responses

Status codes in the 2xx range indicate that the transaction was received, understood, accepted and processed successfully.

200 OK
201 Created
202 Accepted
203 Non-Authoritative Information (since HTTP/1.1)
204 No Content
205 Reset Content
206 Partial Content
207 Multi-Status (WebDAV) (RFC 4918)
226 IM Used (RFC 3229)

3xx Redirection Responses

HTTP status codes in the 3xx range pertain to redirection. The client must take additional action to complete the request.

300 Multiple Choices
301 Moved Permanently
302 Found
303 See Other (since HTTP/1.1)
304 Not Modified
305 Use Proxy (since HTTP/1.1)
306 Switch Proxy
307 Temporary Redirect (since HTTP/1.1)
308 Resume Incomplete

4xx Client Error

HTTP status codes in the 4xx range indicate that a problem occurred with the request.

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
416 Requested Range Not Satisfiable
417 Expectation Failed
418 I'm a teapot (RFC 2324)
422 Unprocessable Entity (WebDAV) (RFC 4918)
423 Locked (WebDAV) (RFC 4918)
424 Failed Dependency (WebDAV) (RFC 4918)
425 Unordered Collection (RFC 3648)
426 Upgrade Required (RFC 2817)
428 Precondition Required
429 Too Many Requests
431 Request Header Fields Too Large
444 No Response
449 Retry With
450 Blocked by Windows Parental Controls
499 Client Closed Request

5xx Server Error

Error codes in the 5xx range indicate that server is aware that it has encountered an error or is otherwise incapable of performing the request.