How are HTTP response codes grouped and what do they mean?

HTTP status codes are divided into five main groups based on the first digit of the code:

• 1xx (Informational): indicate that the request has been received and the process is continuing (e.g., 100 Continue).
• 2xx (Successful): the request was successfully processed (e.g., 200 OK, 201 Created).
• 3xx (Redirection): the client must take additional actions to complete the request (e.g., 301 Moved Permanently, 302 Found).
• 4xx (Client Error): there was an error on the client's side, such as a bad request or lack of access (e.g., 400 Bad Request, 401 Unauthorized, 404 Not Found).
• 5xx (Server Error): there was an error on the server side while processing the request (e.g., 500 Internal Server Error, 503 Service Unavailable).

This division helps quickly understand the nature of the response and take appropriate measures.