Common HTTP status codes include 200 (OK), 404 (Not Found), 500 (Internal Server Error), and 403 (Forbidden), each indicating different outcomes of an HTTP request.

HTTP status codes are critical components of web development, providing standardized responses from servers to clients about the outcome of HTTP requests. Understanding common HTTP status codes is essential for developers to effectively communicate the status of requests. The most frequently used status code is 200 (OK), which indicates that the request was successful, and the server returned the requested resource. Another important status code is 404 (Not Found), which signifies that the requested resource could not be found on the server. This is often displayed as a user-friendly error page when users navigate to a nonexistent URL. The status code 500 (Internal Server Error) indicates that an unexpected condition was encountered on the server, preventing it from fulfilling the request. Additionally, the 403 (Forbidden) status code informs the client that access to the requested resource is denied, often due to lack of permissions. Other notable codes include 201 (Created) for successful resource creation, 204 (No Content) for successful requests without a body, and 301 (Moved Permanently) for URL redirection. By utilizing these status codes correctly, developers can enhance user experience and improve error handling in their web applications.