All HTTP status codes
4xx Client Error
RFC 9110
404 Not Found
The requested resource could not be found on the server.
What it means
HTTP 404 Not Found is returned when the server cannot find the requested resource. The most famous error code on the web — it tells the client the URL is invalid or the resource has been removed.
When it's used
Missing pages, deleted resources, mistyped URLs, or genuinely non-existent endpoints.
Common causes
- URL typo by user
- Page or product deleted
- Broken internal link
- Sitemap referencing removed URL
- Old indexed URL no longer valid
How to fix it
- Implement a custom 404 page with helpful navigation
- Use 301 redirects for moved content (never let it 404)
- Audit and remove broken internal links monthly
- Submit deleted URLs in Google Search Console to speed deindexing
Example response
HTTP/1.1 404 Not Found Content-Type: text/html
SEO impact
Critical to manage. Excessive 404s waste crawl budget. Use 301 to redirect removed pages whenever possible.