HTTP Status Codes Guide: 200, 301, 404, 500 and SEO

HTTP status codes are short signals sent by a server to explain what happened to a request. They matter for APIs, browsers, crawlers, redirects, broken links and technical SEO audits.

Open the HTTP status code lookup

The five status code families

  • 1xx: informational responses.
  • 2xx: successful requests such as 200 OK.
  • 3xx: redirects such as 301 and 302.
  • 4xx: client-side issues such as 404 or 429.
  • 5xx: server-side failures such as 500 or 503.

SEO codes to watch

200 means the page can load normally. 301 is usually the right permanent redirect. 404 is acceptable for removed pages, but important URLs should redirect or be restored. 503 can protect SEO during temporary maintenance when used correctly.

API debugging checklist

When an API fails, record the method, URL, request body, headers, response body and status code. The status code tells you where to look first: authentication, validation, rate limits, routing or server logs.