GLOSSARY TERM
What is 404 Error?
Definition
An HTTP status code indicating the requested page does not exist. The browser still loads a response (often the site's "Not Found" page) but with a 404 status header.
Why it Matters for AI Search
A few 404s are normal; many 404s waste crawl budget and signal site neglect. Always 301-redirect deleted pages to the closest relevant alternative. Soft 404s — pages that look "not found" but return HTTP 200 — are an even worse hidden problem.
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