Definition

A 404 error is an HTTP response with status code 404 ("Not Found"), returned when a server cannot find the requested URL. Google interprets 404s as a clear signal that the URL no longer exists and drops it from the index over time.

Google's documentation says 404 errors are a normal part of the web and are not a problem in themselves — every site accumulates them as old URLs are removed. The closely related 410 ("Gone") status indicates the URL is permanently gone and is processed slightly faster, but in practice Google treats 404 and 410 similarly. The pattern to avoid is the soft 404, where a URL serves a 200 response while displaying "page not found" content — that wastes crawl budget because Google cannot tell the URL is gone.

Examples

• Removed product page

  A retailer permanently removes a discontinued product. The URL `/shoes/old-runner` now returns HTTP 404 with a friendly "product not available" page. Google recrawls the URL, marks it as Not Found in Search Console, and drops it from the index after several weeks.

Sources

• Google Search Central — HTTP status codes

Related terms

• Soft 404
  A URL that returns an HTTP 200 status but displays content telling the user the page doesn't exist. Google treats it as a 404.
• 301 Redirect
  A permanent redirect — an HTTP 301 status code telling clients and search engines that a URL has moved permanently to a new location.
• Indexing
  The process by which a search engine analyses a fetched page and stores information about it so the page can later be returned in search results.

Where QueryCatch uses this

• SEO Audit