Custom 404 Page Checker

It's a page that reads as "not found" to a human — or doesn't exist at all — but answers with HTTP 200 instead of 404. Google explicitly calls this out in its own documentation as a problem: it can't reliably tell a soft-404 apart from a real page, so it may keep crawling and even indexing URLs that lead nowhere.

It's one of the most common soft-404 patterns. From a visitor's side it feels harmless — they land somewhere, not on an error page — but search engines see a 200-status homepage at a URL that was never meant to exist, which muddies which URLs are actually real and can dilute how the homepage itself is understood.

If the content is gone for good, return a 404 (or 410 Gone, which is slightly more emphatic about "permanently removed"). If equivalent content now lives at a new URL, a 301 redirect straight to that new URL is correct — that's different from redirecting an arbitrary broken URL to the homepage as a catch-all.

No — it tests one deliberately fake URL to see how your server's default not-found handling behaves. For finding actual broken links and images already on a page, use the Broken Link Checker or Broken Image Checker instead.

Some sites run bot-protection services that intercept unfamiliar-looking requests before they ever reach the site's own 404 logic. A blocked result is inconclusive, not a finding about your 404 handling either way.