HTTP 404 Not Found: what it means for crawlers
404 Not Found means the server has no resource at that URL. It is the correct, healthy response for genuinely missing pages — crawlers expect some 404s. Problems arise when important pages 404 by accident, when removed pages should signal 410, or when 'not found' pages wrongly return 200.
What 404 means
404 Not Found is the server saying 'there is nothing at this URL'. Some 404s are completely normal — old links, mistyped URLs, probing bots. Crawlers handle 404 gracefully: they stop trying to index the URL and revisit less often over time.
404 vs 410 vs 301
Choose the response that matches intent. 404 means 'not found, maybe temporary'. 410 Gone means 'deliberately and permanently removed' — a stronger signal that can speed removal from the index. 301 means 'moved' and should point to the equivalent new URL. Do not 301 everything to the homepage; an irrelevant redirect is treated like a soft 404.
- 404 — missing, possibly temporary
- 410 — intentionally and permanently gone
- 301 — moved; redirect to the true equivalent URL
Operator checklist
Make sure your 'not found' page returns a real 404 status (not a 200). Investigate 404 spikes on previously-valid URLs. Map removed content to 301s where an equivalent exists, or 410s where it is truly gone. Fix internal links that point at 404s.
How it appears in analytics and logs
A 404 tells a crawler the URL is not there; it will typically retry occasionally, then drop it. A spike of 404s on URLs that used to work signals broken links, a bad deploy, or a migration without redirects.
Diagnostic use case
Distinguish healthy 404s from accidental ones on important URLs, and decide when to use 410 Gone or a 301 redirect instead.
What WebmasterID can help detect
WebmasterID can highlight a rise in 404s and which paths crawlers are hitting, so a broken migration or dead internal link is visible quickly rather than silently bleeding crawl budget.
Common mistakes
- Returning 200 on a 'not found' page (soft 404).
- Bulk-redirecting dead URLs to the homepage instead of a relevant target.
- Ignoring 404 spikes that indicate a broken deploy or migration.
Privacy and accuracy notes
Status codes carry no personal data. WebmasterID reports 404 patterns for crawler and overall traffic without exposing individual visitors.
Related pages
- HTTP 200 OK: what it means for crawlers
200 OK means the request succeeded and the server returned the resource. For crawlers it is the green light to process and potentially index a page. The subtle trap is the soft 404 — an error or empty page served with a 200 status, which wastes crawl budget and pollutes the index.
- robots.txt basics: what it does and what it cannot do
robots.txt is a plain-text file at your site root that tells compliant crawlers which paths they may request. This page covers the directives, how user-agent groups are matched, and the limits that trip people up: robots.txt is advisory, it does not hide pages from search, and it is not a security boundary.
- Spoofed and fake user agents: what to watch for
Spoofing a user agent is trivial — any client can claim to be Googlebot or a normal browser. This page explains why spoofing happens, the common fake-crawler patterns, and the verification methods that turn a claimed identity into a confirmed one.
- Website observability
Spot 404 spikes and the paths crawlers are hitting.
Sources and verification notes
Last reviewed 2026-06-24. Facts are checked against primary/official sources where available; uncertain specifics are marked “Data not yet verified” rather than guessed.