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404 Not Found

4xx client error

The server can't find anything at the requested URL.

404 is the web's most familiar error: there is nothing at this URL, or the server won't say there is. It isn't necessarily permanent — the resource might exist later — which is what separates it from 410 Gone.

For APIs, a 404 should mean the route or the specific record doesn't exist, not that a search came back empty.

Class4xx Client Error
Retry?No — change the request first
Cacheable by defaultYes (heuristically, per RFC 9110)
Response bodyAllowed
Defined inRFC 9110 §15.5.5 — 404 Not Found
Example response
HTTP/1.1 404 Not Found
Content-Type: application/json
Content-Length: 21

{"error":"Not Found"}

Common causes

  • A typo, a broken link, or a link to a page that moved without a redirect.
  • Case-sensitive paths: /About and /about are different URLs on most servers.
  • A single-page app served without a fallback, so deep links 404 on refresh.
  • A deploy that dropped a file or route.
  • An API record that was deleted or never existed.

How to fix it

  1. Redirect moved pages to their new URLs with 301.
  2. For single-page apps, serve index.html for unknown routes and let the app render its own not-found view.
  3. Return a real 404 status for missing pages — a 'not found' page served with 200 is a soft 404 that search engines flag.
  4. Make the 404 page useful: a search box and links to popular pages.

Useful here: HTTP Status Checker

Send a 404 from your server

Express
res.status(404).json({ error: "Not Found" });
Next.js route handler
return Response.json({ error: "Not Found" }, { status: 404 });
Flask
return {"error": "Not Found"}, 404
Go net/http
http.Error(w, "Not Found", http.StatusNotFound)
nginx
return 404;

Check what a URL returns

Print just the status line from the command line, or check a whole list of URLs at once, with their response headers, in the HTTP Status Checker.

curl -sI https://example.com/your-path | head -n 1

Frequently asked questions

Do 404s hurt SEO?

Not in themselves — Google expects them for pages that don't exist. What hurts is internal links pointing at 404s, and important pages that 404 instead of redirecting.

404 vs 410?

404: not here, and it may or may not come back. 410: deliberately removed and not coming back. Google drops 410 URLs a little faster.

What is a soft 404?

A page that says 'not found' but returns 200, or that redirects every missing URL to the homepage. Search Console flags these because the status contradicts the content.

Related status codes