HTTP Status Messages
When a browser requests a service from a web server, an error might occur, and the server might return an error code like «404 Not Found».
It is common to name these errors HTML error messages.
But these messages are something called HTTP status messages. In fact, the server always returns a message for every request. The most common message is 200 OK.
Below is a list of HTTP status messages that might be returned:
| Message: | Description: |
| 100 Continue | The server has received the request headers, and the client should proceed to send the request body |
| 101 Switching Protocols | The requester has asked the server to switch protocols |
| 103 Early Hints | Used with the Link header to allow the browser to start preloading resources while the server prepares a response |
2xx: Successful
| Message: | Description: |
| 200 OK | The request is OK (this is the standard response for successful HTTP requests) |
| 201 Created | The request has been fulfilled, and a new resource is 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 successfully processed, but is returning information that may be from another source |
| 204 No Content | The request has been successfully processed, but is not returning any content |
| 205 Reset Content | The request has been successfully processed, but is not returning any content, and requires that the requester reset the document view |
| 206 Partial Content | The server is delivering only part of the resource due to a range header sent by the client |
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 | Indicates the requested page has not been modified since last requested |
| 307 Temporary Redirect | The requested page has moved temporarily to a new URL |
| 308 Permanent Redirect | The requested page has moved permanently to a new URL |
4xx: Client Error
| Message: | Description: |
| 400 Bad Request | The request cannot be fulfilled due to bad syntax |
| 401 Unauthorized | The request was a legal request, but the server is refusing to respond to it. For use when authentication is possible but has failed or not yet been provided |
| 402 Payment Required | Reserved for future use |
| 403 Forbidden | The request was a legal request, but the server is refusing to respond to it |
| 404 Not Found | The requested page could not be found but may be available again in the future |
| 405 Method Not Allowed | A request was made of a page using a request method not supported by that page |
| 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 |
| 411 Length Required | The «Content-Length» is not defined. The server will not accept the request without it |
| 412 Precondition Failed | The precondition given in the request evaluated to false by the server |
| 413 Request 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. 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 media type is not supported |
| 416 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
| Message: | Description: |
| 500 Internal Server Error | A generic error message, given when no more specific message is suitable |
| 501 Not Implemented | The server either does not recognize the request method, or it lacks the ability to fulfill the request |
| 502 Bad Gateway | The server was acting as a gateway or proxy and received an invalid response from the upstream server |
| 503 Service Unavailable | The server is currently unavailable (overloaded or down) |
| 504 Gateway Timeout | The server was acting as a gateway or proxy 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 used in the request |
| 511 Network Authentication Required | The client needs to authenticate to gain network access |
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HTTP Status Messages
The users may get an error while sending a request to a server. Definitely, the user has seen such messages frequently.
Here you can find the list of Hypertext Transfer Protocol (HTTP) response status codes. These codes are used to respond to the request of the client made to the server. There are 5 classes of HTTP response status codes. Let’s go through each class:
If you receive a response that is not included in this list, this means that it is a non-standard response, perhaps custom to the software of the server.
| Status code | Message | Description |
| 100 | Continue | Means that the server has received request headers and the client should continue to send request body. |
| 101 | Switching Protocols | Means that the client, who made a request, has asked the server to change protocols. |
| 103 | Checkpoint | Means that it is used in the resumable requests proposal to resume aborted PUT or POST requests. |
2xx: Successful
| Status code | Message | Description |
| 200 | OK | Means that the request is OK. It is standard response for successful HTTP requests. |
| 201 | Created | Means that the request has been fulfilled and a new resource is created. |
| 202 | Accepted | Means that the request has been accepted for processing, but the processing is going on. |
| 203 | Non-Authoritative Information | Means that the request has been successfully processed, but it is returning information which may be from another source. |
| 204 | No Content | Means that the request has been successfully processed, but it is not giving any content. |
| 205 | Reset Content | Means that the request has been processed, but it is not returning any content and it requires that the requester reset the document view. |
| 206 | Partial Content | Means that the server commits only a part of the resource, because of a range header, which was sent by the client. |
3xx: Redirection
| Status code | Message | Description |
| 300 | Multiple Choices | Is a link list which means that the user can select a link and go there. It can contain maximum five addresses. |
| 301 | Moved Permanently | Means that the page has been moved to a new URL. |
| 302 | Found | Means that the requested page has been moved to a new URL temporarily. |
| 303 | See Other | Means that the requested page can be found in another URL. |
| 304 | Not Modified | Means that the requested page hasn’t been modified since the last request. |
| 306 | Switch Proxy | Is not used anymore. |
| 307 | Temporary Redirect | Means that the requested page has been moved to a new URL temporarily. |
| 308 | Resume Incomplete | Is used in resumable requests proposal to continue aborted PUT or POST requests. |
4xx: Client Error
| Status code | Message | Description |
| 400 | Bad Request | Means that the request can be fulfilled because of the bad syntax. |
| 401 | Unauthorized | Means that the request was legal, but the server is rejecting to answer it. For the use when authentication is required and has failed or has not yet been provided. |
| 402 | Payment Required | Is reserved for a future use. |
| 403 | Forbidden | Means that the request is legal, but the server is rejecting to answer it. |
| 404 | Not Found | Means that the requested page cannot be found at the moment, but it may be available again in the future. |
| 405 | Method Not Allowed | Means that the request was made of a page that uses an unsupported request method for that page. |
| 406 | Not Acceptable | Means that the server can only generate an answer which the client doesn’t accept. |
| 407 | Proxy Authentication Required | Means that the client first authenticate itself with the proxy. |
| 408 | Request Timeout | Means that the server timed out waiting for the request. |
| 409 | Conflict | Means that the request cannot be completed, because of a conflict in the request. |
| 410 | Gone | Means that the requested page is not available anymore. |
| 411 | Length Required | Means that the content length is not defined and the server won’t accept the request without it. |
| 412 | Precondition Failed | Means that precondition, which is given in the request, is evaluated to false by the server. |
| 413 | Request Entity Too Large | Means that the request entity is too large and that’s why the server won’t accept the request. |
| 414 | Request-URI Too Long | Means that the URL is too long and that’s why the server won’t accept the request. It happens when you convert a POST request to a GET request with a long query information. |
| 415 | Unsupported Media Type | Means that the media type is not supported and that’s why the server won’t accept the request. |
| 416 | Requested Range Not Satisfiable | Means that the client asked for a part of the file but the server cannot supply that part. |
| 417 | Expectation Failed | Means that the server cannot meet the requirements of the expected request header field. |
5xx: Server Error
| Status code | Message | Description |
| 500 | Internal Server Error | Is a generic error and users receive this error message when there is no more suitable specific message. |
| 501 | Not Implemented | Means that the server doesn’t recognize the request method or it lacks the ability to fulfill the request. |
| 502 | Bad Gateway | Means that the server was acting as a gateway or proxy and it received an invalid answer from the upstream server. |
| 503 | Service Unavailable | Means that the server is not available now (It may be overloaded or down). |
| 504 | Gateway Timeout | Means that the server was acting as a gateway or proxy and it didn’t get answer on time from the upstream server. |
| 505 | HTTP Version Not Supported | Means that the HTTP protocol version, used in the request, is not supported by the server. |
| 511 | Network Authentication Required | Means that the client needs to authenticate to gain network access. |
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