404 Error

404 Error is the HTTP status code a server returns when the requested URL does not exist.

A 404 means the server received the request, understood it, but found no resource at that address. It is a normal and expected part of the web; pages get removed, links get mistyped, and old URLs go stale. Returning a clean 404 is the correct response when a page is genuinely gone and you do not have a relevant replacement to redirect to.

For SEO, scattered 404s are not a penalty. Search engines expect some missing URLs and will simply drop them from the index after repeated crawls. What matters is that the status code is honest: the response must actually carry a 404 (or 410 Gone) in its header so crawlers know to deindex the URL. A helpful 404 page that links back to navigation, search, or popular content keeps users from bouncing.

The problem to watch for is the soft 404, a page that returns a 200 OK status while showing a "not found" message. Search engines treat that as a live page, waste crawl budget on it, and may index empty content. If a removed page has a strong replacement, send a 301 redirect instead of a 404; if it is simply gone, let the 404 stand rather than redirecting everything to the homepage, which itself creates soft 404 signals.

Related: 301 Redirect, HTTP Status Codes Reference, Indexation Checks