HTTP Status Checker

HTTP status codes are three-digit numbers returned by a web server in response to a client's request, indicating the outcome of the request. They are grouped by category: 1xx (informational), 2xx (success — e.g. 200 OK), 3xx (redirection — e.g. 301 Moved Permanently, 302 Found), 4xx (client errors — e.g. 404 Not Found, 403 Forbidden), and 5xx (server errors — e.g. 500 Internal Server Error, 503 Service Unavailable). The status code tells clients and search engines how to interpret the response.

A 301 Moved Permanently redirect tells browsers and search engines that the resource has permanently moved to a new URL. Search engines transfer most of the original page's link equity (PageRank) to the new URL and update their index. A 302 Found redirect indicates a temporary move — search engines continue indexing the original URL and do not transfer link equity. Use 301 for permanent redirects (domain migrations, URL restructuring) and 302 only for genuinely temporary situations.

A 404 Not Found response tells search engines the page does not exist. Crawlers will eventually de-index 404 pages. Soft 404s — pages that display 'not found' content but return a 200 OK status — are a common problem that confuses crawlers. If a URL has been permanently removed, return a proper 404 or 410 (Gone). If it has moved, use a 301 redirect. Excessive 404 errors waste crawl budget and can signal poor site maintenance to search engines.

503 Service Unavailable indicates the server is temporarily unable to handle the request, typically due to maintenance or overload. When combined with a Retry-After header specifying when the server will be available, it tells search engines to come back later without de-indexing the page — unlike a 404 which signals permanent removal. Use 503 during scheduled maintenance windows to preserve search engine rankings. Avoid using 503 for extended periods as it can eventually lead to de-indexing.