404, 410 and soft 404
A 404 only says the resource is missing, without saying whether that is temporary or permanent. A 410 (Gone) signals a deliberate, permanent removal. Google handles both the same way: like every 4xx code except 429, they tell Google the content does not exist, so the URL is removed from the index and crawled less and less often.
A soft 404 is a different trap: the page says "not found" or shows almost nothing, but the server returns 200 (success). Google detects it and flags it in Search Console, because that false success muddles indexing.
Do 404s hurt SEO?
404s on URLs that never existed or on pages you really removed are normal on any living website. They become a problem in three situations: when a page that earned backlinks starts returning 404, wasting the value of those links; when your own internal links lead to 404s, which hurts users and crawling; and when an important page turns into a 404 by mistake, during a redesign or a slug change.
Finding and triaging 404s
- Search Console: the Page indexing report lists "Not found (404)" URLs Google knows about.
- A crawler: finds broken internal links and the page that contains them.
- Google Analytics 4: filter page views by your 404 page title to see which bad URLs people actually hit.
- A backlink tool: isolate external links pointing to 404 URLs.
- Decision: a 301 when an equivalent page exists, otherwise a 404 or 410.
A helpful 404 page
Keep a real 404 status code, explain plainly that the page no longer exists, and offer a search bar, links to the main sections and a way to get in touch. Do not automatically redirect every 404 to the homepage: visitors get confused and Google may treat those redirects as soft 404s anyway.