Common HTTP status codes are as follows:

1. Successful status code:
2. 200-the server returns the webpage successfully
3. 304-not modified
4. Status Code of failure:
5. 404-the requested webpage does not exist
6. 503-the server is temporarily unavailable
7. 500-Internal Server Error

 

The following is not very common. Remember the above ones and you will be OK. If there is a bug, try again.

 

Other status codes are as follows:

 

1xx (temporary response)

The status code that indicates a temporary response and requires the requester to perform the operation to continue.

1. 100 (CONTINUE) the requester shall continue to make the request. The server returns this code, which means that the server has received the first part of the request and is waiting to receive the remaining part. (New HTTP 1.1)
2. 101 (switching protocols switching protocol) the requester has requested the server switching protocol, and the server has confirmed and is ready to switch. (New HTTP 1.1)

 

 

2XX (successful)

 

The status code indicating that the server has successfully processed the request.

 

1. 200 (successful) the server has successfully processed the request. Generally, this indicates that the server provides the requested webpage.
2. 201 (created) The request is successful and the server has created a new resource.
3. 202 (accepted) the server has accepted the request but has not processed it.
4. 203 (unauthorized information) the server has successfully processed the request, but may return information from another source.
5. 204 (NO content) The server successfully processed the request, but did not return any content.
6. 205 (reset content) The server successfully processed the request, but did not return any content. Unlike the 204 response, this response requires the requester to reset the document view (for example, clear the form content to enter new content ).
7. 206 (partial content) The server successfully processes some GET requests.

3xx (redirected)

To complete the request, you must perform further operations. These status codes are usually always redirected. Google recommends that you use fewer than five redirection entries for each request.

 

1. 300 (multiple options) the server can perform multiple operations according to the request. The server selects an operation based on the user agent or provides an operation list for the user agent to select.
2. 301 (permanently moved) requested webpage has been permanently moved to a new location. When the server returns this response (as a response to a get or head request), it automatically redirects the requester to a new location. You should use this code to notify googlebot that a webpage or website has been permanently moved to a new location.
3. The 302 (temporary mobile) server is currently responding to requests from different locations, but the requester should continue to use the original location for subsequent requests. Similar to code 301 In response to get and head requests, this code automatically redirects the requester to different locations. However, because googlebot continues to capture the original location and indexed it, you should not use this code to notify googlebot that a page or website has been moved.
4. 303 (view other locations) The server returns this code when the requester must perform separate GET requests for different locations to retrieve responses. For all requests except HEAD requests, the server automatically redirects to other locations.
5. 304 (not modified) the requested webpage has not been modified since the last request. When the server returns this response, no webpage content is returned.
6. 305 (using a proxy) the requester can only use a proxy to access the requested webpage. If the server returns this response, the server also specifies the proxy that the requester should use.
7. 307 (temporary redirection) the server is currently responding to requests from different locations, but the requester should continue to use the original location for subsequent requests. Similar to code 301 In response to get and head requests, this code automatically redirects the requester to different locations. However, because googlebot continues to capture the original location and indexed it, you should not use this code to notify googlebot that a page or website has been moved.

4xx (request error)

These status codes indicate that the request may fail and the server may be unable to process the request.

 

1. 400 (incorrect request) the server does not understand the request syntax.
2. 401 (unauthorized) requests require authentication. After logon, the server may return this response to the page.
3. 403 (Forbidden) The server rejects the request.
4. 404 (not found) The server cannot find the requested webpage. For example, if the request is for a webpage that does not exist on the server, the server usually returns this code.
5. 405 (method disabled) disable the method specified in the request.
6. 406 (unacceptable) the requested content features cannot be used to respond to the requested webpage.
7. 407 (proxy authorization required) this status code is similar to 401 (unauthorized), but it specifies that the requester should use the proxy for authorization. If the server returns this response, the server also specifies the proxy that the requester should use.
8. 408 (request timeout) The server timed out while waiting for the request.
9. 409 conflict occurs when the server completes the request. The server must contain information about conflicts in the response. The server may return this code when responding to a put request that conflicts with the previous request, and provides a list of differences between the two requests.
10. 410 (Deleted) If the requested resource has been permanently deleted, the server returns this response. This code is similar to the 404 (not found) code, but sometimes it may replace the 404 code when the resource exists but does not exist now. If the resource has been permanently deleted, you should use code 301 to specify a new location for the resource.
11. The 411 (valid length required) server will not accept requests that contain header fields with invalid Content Length.
12. 412 (not meeting the prerequisites) the server does not meet one of the prerequisites set by the requester in the request.
13. 413 (the Request Entity is too large) The server cannot process the request because the request entity is too large and exceeds the server's processing capability.
14. 414 (the requested URI is too long) The request URI (usually the URL) is too long and the server cannot process it.
15. 415 (unsupported media type) The request format is not supported by the request page.
16. 416 (the request range does not meet the requirements) If the request is for a webpage's invalid range, the server will return this status code.
17. 417 (not meeting the expected value) the server does not meet the "expected" request header field requirements.

5xx (server error)

These status codes indicate that an internal error occurs when the server attempts to process the request. These errors may be server errors rather than request errors.

 

1. 500 (internal server error) The server encounters an error and cannot complete the request.
2. 501 (not implemented) the server does not have the function to complete the request. For example, if the server cannot identify the request method, the server may return this code.
3. The 502 (error gateway) server, as a gateway or proxy, received an invalid response from the upstream server.
4. 503 (Service unavailable) the server is currently unavailable (due to overload or downtime maintenance ). This is usually a temporary state.
5. 504 (gateway timeout) The server acts as a gateway or proxy and fails to receive requests from the upstream server in a timely manner.
6. 505 (HTTP Version Not Supported) the server does not support the HTTP protocol version used in the request.