About
About soft404scan
A free, open detector for soft 404s — pages that say "not found" but answer crawlers with HTTP 200.
A soft 404 is one of the quietest SEO bugs: the page tells a visitor the content is gone, but the
server returns 200 OK (or redirects the URL to the homepage). Engines can't tell it's missing, so they
keep crawling and indexing it and flag a "Soft 404" in Search Console.
soft404scan pairs your URL with a synthetic, guaranteed-missing URL in the same directory and compares them — status code, redirect target, and content similarity — so it can tell a real page from a 200 that is really a not-found page. It reads server-rendered HTML only and flags single-page-app shells rather than guessing. Every rule is published, and there is no fake score. It runs on Cloudflare, fetches only public URLs, and keeps no logs.