< br > < br > < strong > one, what is the HTTP status code < / strong > < br > < br > HTTP status code (HTTP Status Code) is the server’s response to the browser request. When you visit a website, the browser sends a request to the site’s server, and the server responds to the browser’s request with a three-digit code. This is the HTTP status code. Under normal circumstances, we will not see these status codes, so when it occurs, there is generally an error in the website, which requires site managers to distinguish, understand and debug. < br > < br > understanding status codes and how to use them will help you diagnose website errors quickly, thereby minimizing downtime. You can even use some of these status codes to help search engines and users visit your site. For example, 301redirects will tell search engines and users that one page is permanently moved to another page, and the correctness of HTTP status codes It is also related to the friendliness of SEO. < br > < br > < strong > II. Common status code categories < / strong > < br > < br > 1, 1xx-status message (Informational): connection is in progress. < br > 2, 2xx-success message (OK): the request completed successfully and the server gave the browser the expected response. < br > 3, 3xx-redirect (Redirection): this request was received, but it needs to be redirected. < br > 4, 4xx-client error (Client Error): the request has been made, but the page is invalid, which is the site’s error and usually occurs when the page does not exist. < br > 5, 5xx-Server error (Server Error): the client’s request is valid, but the server failed to complete the request. < br > < br > < strong > III. List of HTTP status codes < / strong > < br > < br > < span > 1, 1xx-status information < / span > < br > < br > 100 Continue-continue to execute the request. < br > 101 Switching Protocols-switching protocol. According to the request of the client, the server can only switch to a more advanced protocol. For example: switch to the new version of the HTTP protocol. < br > < br > < span > 2, 2xx-success message < / span > < br > < br > 200 OK-request succeeded. Commonly used for GET and POST requests. < br > 201 Created-created. A new resource was successfully requested and created. < br > 202 Accepted-accepted. The request has been accepted, but processing has not been completed. < br > 203 Non-Authoritative Information-unauthorized information. The request was successful, but the meta information returned was not on the original server, but a copy. < br > 204 No Content-No content. The server successfully processed but did not return content. If the page is not updated, you can ensure that the browser continues to display the current document. < br > 205 Reset Content-resets content. The server is processed successfully, and the user terminal (for example, browser) should reset the document view. The form field of the browser can be cleared by this return code. < br > 206 Partial Content-partial content. The server successfully processed some GET requests. < br > < br > < span > 3, 3xx-redirect < / span > < br > < br > 300 Multiple Choices-multiple choices. The requested resource may include a plurality of locations, corresponding to which a list of resource characteristics and addresses can be returned for user terminal (e.g., browser) selection. < br > 301 Moved Permanently-permanent move. The requested resource has been permanently moved to the new URL, the returned information will include the new URL, and the browser will be automatically directed to the new URL. < br > 302 Found-temporary move. Similar to 301, but the resources are moved only temporarily. < br > 303 See Other-View other addresses. Similar to 301, the view is requested using GET and POST. < br > 304 Not Modified-not modified. The requested resource has not been modified, and when the server returns this status code, no resource will be returned. The client usually caches the accessed resources, indicating that the client wants to return only those resources that have been modified after the specified date by providing a header message. < br > 305Use Prox-use proxy. The requested resource must be accessed through an agent. < br > 306 Unused-HTTP status code that has been discarded. < br > 307 Temporary Redirect-temporary redirection. Similar to 302, redirects are requested using GET. < br > < br > < span > 4, 4xx-client error < / span > < br > < br > 400 Bad Request-the syntax of the client request is incorrect and the server cannot understand it. < br > 401 Unauthorized-the request requires authentication of the user. < br > 402 Payment Required-reserved for future use. < br > 403 Forbidden-the server understands the client’s request but refuses to execute it. < br > 404 Not Found-the server cannot find the resource (web page) based on the client’s request. With this code, the site designer can set up a personality page where the resource you requested cannot be found. < br > 405 Method Not Allowed-methods in client requests are prohibited. < br > 406 Not Acceptable-the server cannot complete the request based on the content nature of the client request. < br > 407 Proxy Authentication Required-the request requires the authentication of the agent, similar to 401, but the requestor should use the agent for authorization. < br > 408 Request Time-out-the server waited too long for a request from the client and timed out. < br > 409 Conflict-this code may be returned when the server completes the client’s PUT request, and a conflict occurred while the server was processing the request. < br > 410 Gone-the resource requested by the client no longer exists. 410 is different from 404, if the resource has been permanently deleted and can use 410 code, the website designer can specify the new location of the resource through 301 code. < br > 411 Length Required-the server cannot process request information sent by the client without Content-Length. < br > 412Precondition Failed-A prerequisite error for client request information. < br > 413 Request Entity Too Large-the request was rejected because the requested entity was too large for the server to process. To prevent continuous requests from the client, the server may close the connection. If only the server is temporarily unable to process, it will contain a Retry-After response message. < br > 414 Request-URI Too Large-the requested URL is too long (URL is usually a URL) and cannot be processed by the server. < br > 415 Unsupported Media Type-the server cannot process the media format that came with the request. < br > 416 Requested Range Not Satisfiable-the scope requested by the client is invalid. < br > 417 Expectation Failed-the server cannot satisfy the request header information for Expect. < br > < br > < span > 5, 5xx-server error < / span > < br > < br > 500server-server internal error, unable to complete the request. < br > 501 Not Implemented-the server does not support the requested functionality and cannot complete the request. < br > 502 Bad Gateway-the server acting as a gateway or proxy received an invalid request from the remote server. < br > 503 Service Unavailable-the server is temporarily unable to process client requests due to overloading or system maintenance. The length of the delay can be included in the Retry-After header information of the server. < br > 504 Gateway Time-out-the server acting as a gateway or proxy did not get the request from the remote server in time. < br > 505 HTTP Version not supported-the server does not support the requested version of the HTTP protocol and cannot complete the processing. < br > < br > for every professional SEO staff and webmaster, it is important to understand the HTTP status code for SEO operations. For example, if the website shows an 5xx error, you will immediately know that it is a server problem and troubleshoot it. 4xx errors can affect the user’s experience, so you can customize a 404 friendly page or use 301 redirection to point to the correct page. < / p >
