What the status codes mean
- 2xx — success (200 OK)
- 3xx — redirection (301 moved permanently, 302 found, 304 not modified, 307/308 temporary/permanent redirect)
- 4xx — client errors (403 forbidden, 404 not found, 410 gone, 429 too many requests)
- 5xx — server errors (500 internal error, 502 bad gateway, 503 unavailable)
The checker also shows the content type, cache-control and any X-Robots-Tag header.
Frequently asked questions
Should deleted pages return 404 or 410?
Both tell search engines the page is gone; 410 is slightly more explicit. Redirect only when there is a genuinely equivalent page.
What does a 503 mean for SEO?
A short 503 (for maintenance) is fine. A long-running 503 can lead to pages dropping from the index.