loot.tools
404

Not Found

4xx Client Error

The server can't find the requested resource. The classic broken link.

404 Not Found means the server reached the right host but has nothing at that path. The request was fine - the resource just isn't there, whether it never existed, moved, or was deleted. It's the most familiar error on the web. Note it's distinct from 410 Gone, which says a resource existed but was intentionally removed for good.

What 404 looks like on the wire

GET /blog/launch-post HTTP/1.1
Host: example.com

HTTP/1.1 404 Not Found
Content-Type: text/html
Cache-Control: no-cache

About 4xx Client Error

The request has a problem the client needs to fix, like a bad URL, missing auth, or invalid input.

How to fix 404 Not Found

  • Check the URL for typos, wrong casing, or a missing path segment.
  • Confirm the resource still exists and wasn't moved or deleted.
  • If you moved the page, add a 301 redirect from the old URL.
  • For SPAs, make sure the server rewrites unknown paths to index.html.

Tools that help with 404

URL Builder & Parser
Split the failing URL into segments to spot the typo, doubled slash, or missing path piece.

Where it's defined

404 Not Found is defined in RFC 9110 §15.5.5. MDN's 404 reference covers browser behavior and examples.

Looking for a different one? See the full HTTP status code reference.