- 1xx series(100-199) - informational
- 2xx series - Success
- 3xx series - Redirection
- 4xx series - Client Error
- 5xx series - Server Error
Some commom codes:
200 OK
300 Multiple Choices
301 Moved Permanently
302 Found
304 Not Modified
307 Temporary Redirection
400 Bad Request
401 Unauthorized
403 Forbidden
404 Not Found
410 Gone
500 Internal Server Error
501 Not Implemented
503 Service Unavailable
550 Permission denied