What are a few common HTTP Status Codes and what do they mean?

HTTP responses can be classified into 5 categories:

1xx— Informational Response, means that the request was received by the server and is an indication to the client to wait for the final response.

2xx — Success or Acceptance Response, indicates that the request was successfully received and accepted by the server

3xx — Redirection Response, informs the client that the request has been redirected to another server and the client needs to take explicit action to complete the request

4xx — Client Error Response, indicates that the request sent by the client contains some error

5xx — Server Error Response, indicates that the server received the client request but the request wasn’t completed due to an error on the server-side

A few commonly used status codes

Below is a list of HTTP status codes that I personally see very commonly.

1. 200: OK — the request has succeeded
2. 202: Accepted — indicates that the request has been received and is being processed.
3. 204: No Content — the request has been completed but there is no content to be sent to the client for this request
4. 301: Moved Permanently — indicates that the resource has been permanently moved to a new URL. The new URL is returned as a part of the response header
5. 302: Found — indicates that the resource has been temporarily moved to a new URL. The new URL is returned as a part of the response header
6. 400: Bad Request —is a generic error code that indicates that request will not be processed by the server because it contains a client error
7. 401: Unauthorized — indicates that the request will not be processed since the client does not have authorized access to the target resource
8. 403: Forbidden — indicates that the request will not be processed by the server because it is forbidden due to some client error
9. 404: Not Found — indicates that the server cannot find the resource requested by the client
10. 405: Method Not Allowed — indicates that the server received the request and recognizes the method but refused to process it
11. 408: Request Timeout — indicates that the server did not receive the complete request from a client within a set time period and wants to close the connection
12. 500: Internal Server Error — is a generic server error indicating that something went wrong on the server-side and the server is unable to fulfill the request
13. 501: Not Implemented — indicates that the server does not recognize the requested feature and is unable to process the request
14. 502: Bad Gateway — indicates that the gateway server received an error response from another upstream server
15. 503: Service Unavailable — indicates that the server is temporarily unavailable to handle the request
16. 504: Gateway Timeout — indicates that the gateway server did not receive a response from another upstream server within the timeout period

References:

HTTP response status codes

List of HTTP status codes