HTTP Status Codes

HTTP status codes are three-digit numbers returned by a web server in response to a browser's request. They indicate whether the request was successful, redirected, or resulted in an error. Codes are grouped into five categories: 1xx (Informational), 2xx (Success), 3xx (Redirection), 4xx (Client Error), and 5xx (Server Error).

A 301 redirect means the resource has permanently moved to a new URL, and search engines will transfer ranking to the new URL. A 302 redirect means the resource has temporarily moved, and search engines will keep the original URL indexed. Use 301 for permanent URL changes and 302 for temporary ones.

A 404 Not Found error means the server could not find the requested resource. This typically happens when a page has been deleted, the URL was mistyped, or a link is broken. It is one of the most common HTTP errors users encounter while browsing the web.

A 500 Internal Server Error is a generic server-side error indicating something went wrong on the server, but the server cannot be more specific about the problem. Common causes include misconfigured server files, faulty scripts, database connection issues, or insufficient server resources.

A 401 Unauthorized status means the request lacks valid authentication credentials — the user needs to log in. A 403 Forbidden status means the server understood the request but refuses to authorize it — the user is authenticated but does not have permission to access the resource.