What is an HTTP status code?
HTTP status codes are three-digit responses from the server to the browser-side request. Everyone at some point in time has probably seen the classic 404 page-not-found error. That is an HTTP client error status code and there are a lot more of them.
These http status codes (also called response status codes) serve as a means of communication between the server and the internet browser and there are multiple code classes based on the type of information they are communicating. The differences in classes are indicated through the first digit of the error code, for example: just like a 404, any other 4xx will mean that in some way the page or website could not be reached, while a 2xx means that your request was successfully completed.
The http status codes are divided into the five categories presented below.
- Informational responses (
100–199), - Successful responses (
200–299), - Redirects (
300–399), - Client errors (
400–499), - and Server errors (
500–599).
The below status codes are defined by section 10 of RFC 2616. You can find an updated specification in RFC 7231.
Here are a list of the most common HTTP status codes and their descriptions.
1xx: Information
| Message | Description |
|---|---|
| 100 Continue | Only a part of the request has been received by the server, but as long as it has not been rejected, the client should continue with the request. |
| 101 Switching Protocols | The server switches protocol. |
2xx: Successful
| Message | Description |
|---|---|
| 200 OK | The request is OK. |
| 201 Created | The request is complete, and a new resource is created . |
| 202 Accepted | The request is accepted for processing, but the processing is not complete. |
| 203 Non-authoritative Information | The information in the entity header is from a local or third-party copy, not from the original server. |
| 204 No Content | A status code and a header are given in the response, but there is no entity-body in the reply. |
| 205 Reset Content | The browser should clear the form used for this transaction for additional input. |
| 206 Partial Content | The server is returning partial data of the size requested. Used in response to a request specifying a Range header. The server must specify the range included in the response with the Content-Range header. |
3xx: Redirection
| Message | Description |
|---|---|
| 300 Multiple Choices | A link list. The user can select a link and go to that location. Maximum five addresses . |
| 301 Moved Permanently | The requested page has moved to a new url . |
| 302 Found | The requested page has moved temporarily to a new url . |
| 303 See Other | The requested page can be found under a different url . |
| 304 Not Modified | This is the response code to an If-Modified-Since or If-None-Match header, where the URL has not been modified since the specified date. |
| 305 Use Proxy | The requested URL must be accessed through the proxy mentioned in the Location header. |
| 306 Unused | This code was used in a previous version. It is no longer used, but the code is reserved. |
| 307 Temporary Redirect | The requested page has moved temporarily to a new url. |
4xx: Client Error
| Message | Description |
|---|---|
| 400 Bad Request | The server did not understand the request. |
| 401 Unauthorized | The requested page needs a username and a password. |
| 402 Payment Required | You can not use this code yet. |
| 403 Forbidden | Access is forbidden to the requested page. |
| 404 Not Found | The server can not find the requested page. |
| 405 Method Not Allowed | The method specified in the request is not allowed. |
| 406 Not Acceptable | The server can only generate a response that is not accepted by the client. |
| 407 Proxy Authentication Required | You must authenticate with a proxy server before this request can be served. |
| 408 Request Timeout | The request took longer than the server was prepared to wait. |
| 409 Conflict | The request could not be completed because of a conflict. |
| 410 Gone | The requested page is no longer available . |
| 411 Length Required | The “Content-Length” is not defined. The server will not accept the request without it . |
| 412 Precondition Failed | The pre condition 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-url Too Long | The server will not accept the request, because the url is too long. Occurs when you convert a “post” request to a “get” request with a long query information . |
| 415 Unsupported Media Type | The server will not accept the request, because the mediatype is not supported . |
| 416 Requested Range Not Satisfiable | The requested byte range is not available and is out of bounds. |
| 417 Expectation Failed | The expectation given in an Expect request-header field could not be met by this server. |
5xx: Server Error
| Message | Description |
|---|---|
| 500 Internal Server Error | The request was not completed. The server met an unexpected condition. |
| 501 Not Implemented | The request was not completed. The server did not support the functionality required. |
| 502 Bad Gateway | The request was not completed. The server received an invalid response from the upstream server. |
| 503 Service Unavailable | The request was not completed. The server is temporarily overloading or down. |
| 504 Gateway Timeout | The gateway has timed out. |
| 505 HTTP Version Not Supported | The server does not support the “http protocol” version. |
