What HTTP response codes do you know? How can they be grouped?

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

1xx — Informational (e.g., 100 Continue) 2xx — Success (200 OK, 201 Created) 3xx — Redirection (301 Moved Permanently, 302 Found) 4xx — Client errors (400 Bad Request, 401 Unauthorized, 404 Not Found) 5xx — Server errors (500 Internal Server Error, 503 Service Unavailable)

Examples of popular codes:

• 200 OK — request successfully processed
• 201 Created — resource successfully created
• 400 Bad Request — invalid request
• 401 Unauthorized — authentication required
• 403 Forbidden — access denied
• 404 Not Found — resource not found
• 500 Internal Server Error — internal server error
• 503 Service Unavailable — service temporarily unavailable

This division helps quickly understand the result of the request and handle the response correctly.