- 1xx — Informational responses.
- 2xx — Successful responses: The action was successfully received, understood, and accepted.
- 3xx — Redirection responses.
- 4xx — Request failure responses: The request contains bad syntax or cannot be fulfilled at the server.
- 5xx — Server failure responses: The server failed to fulfill an apparently valid request.
- 6xx — Global failure responses: The request cannot be fulfilled at any server.