Status codes are the first clue in an HTTP header check. They explain whether a request succeeded, redirected, failed, or was blocked.
Use the HTTP Header Check tool to see the status code and related headers. A status code is useful on its own, but the surrounding headers often explain the real cause.
200 OK means the request succeeded. 301 Moved Permanently and 302 Found mean the server is redirecting the browser. 403 Forbidden means the server understood the request but refused access. 404 Not Found means the path was not found. 429 Too Many Requests means rate limiting. 500 Internal Server Error means the server application failed. 503 Service Unavailable often means maintenance, overload or upstream failure.
For SEO, redirects and error codes deserve attention. A broken 301 chain can slow crawling. A 404 on an important page can lose traffic. A 500 or 503 during a crawl can make search engines temporarily reduce trust in the page availability.
Status codes can vary by user agent, IP address, country, cookies and request method. A page may respond differently to HEAD, GET, bots and logged-in users.
Use 301 for permanent moves and 302 for temporary redirects. Search engines treat them differently over time.
Yes. A server can return 200 for an error page if the application handles failures incorrectly.
Some servers treat HEAD requests differently, require cookies, or block automated user agents.
A redirect loop happens when URLs keep redirecting back and forth without reaching a final page.
Persistent 5xx errors and broken redirects are especially harmful because they prevent reliable crawling.