HTTP Status Codes

Definition

HTTP status codes are standardized three-digit responses sent by web servers to indicate the result of a browser's request. They're grouped into five categories: 1xx (Informational) — request received, processing; 2xx (Success) — 200 OK is the most common, meaning the page loaded successfully; 3xx (Redirection) — 301 (permanent redirect) and 302 (temporary redirect) tell browsers to go to a different URL; 4xx (Client Errors) — 404 (Not Found) means the page doesn't exist, 403 (Forbidden) means access denied, 410 (Gone) means permanently removed; 5xx (Server Errors) — 500 (Internal Server Error) and 503 (Service Unavailable) indicate server problems. For SEO, the most important status codes are: 200 (healthy pages), 301 (permanent redirects that pass link equity), 404 (broken links that waste crawl budget), and 503 (tell Google to retry later during maintenance).