HTTP 404 — Not Found
4xx Client Error
What it means
The server has no resource at this URL. It does not say whether the resource ever existed or ever will.
What to do about it
Check for a typo, a missing trailing slash, a case-sensitivity mismatch, or a route that was never registered. If the page moved, return a 301 to the new location instead of a 404 — that preserves search rankings and does not strand inbound links.
Where it sits
404 belongs to the 4xx family: The request contains something the server will not or cannot process. The fix is normally on the client side.
HTTP/1.1 404 Not FoundChecking it yourself
# see the status code and headers only
curl -sI https://example.com/path
# follow redirects and print each hop
curl -sIL -o /dev/null -w "%{http_code} %{url_effective}\n" https://example.com/path
# JavaScript
const r = await fetch(url);
console.log(r.status, r.statusText);