HTTP Status Code

What Is an HTTP Status Code?

Incorrect HTTP status codes are among the most common technical SEO errors and can cause Google not to index pages, ignore redirects, or waste crawl budget. Especially during website relaunches and URL changes, correct 301 redirects determine whether hard-earned ranking power is preserved. Regular monitoring of status codes via Search Console protects you from undetected problems.

HTTP status codes are three-digit numbers that a server returns in response to a URL request. They indicate whether the request was successful or which error occurred. The most important codes for SEO are: 200 (OK, page found), 301 (permanent redirect), 302 (temporary redirect), 404 (page not found), 410 (page deleted), 500 (server error), 503 (service unavailable). Google uses HTTP status codes to decide whether and how a page is indexed.

Technically, HTTP status codes are essential for crawl decisions: a 200 code tells Googlebot “this page is live and indexable.” A 404 signals “this page does not exist.” A 301 means “this URL has been permanently moved” — Google then learns to index the new URL instead of the old one. A 503 code communicates that the server is temporarily unavailable — Google waits and crawls again later. Incorrect status codes (e.g. a deleted page with a 200 code) confuse Google and can damage rankings.

For SEO optimization: regularly check the HTTP status codes of your pages via Google Search Console or tools like Screaming Frog. Fix 404 errors with correct 301 redirects or by recreating the content. Use 301s for permanent URL changes and 302s only for temporary redirects. Avoid 5xx errors through regular server maintenance and monitoring. A clean status code setup is important for crawl efficiency and indexing quality.