What class of response is HTTP 404?

HTTP 404 is a 4xx Client Error response. These indicate a client-side error.

How do I fix HTTP 404 Not Found?

HTTP 404 is a client error. Verify the request URL, method, headers, and body are correct. Consult the API documentation for the endpoint.

Is HTTP 404 an error?

Yes, HTTP 404 is an error — specifically a 4xx Client Error code.

HTTP 404 Not Found: What It Means and When You See It

Quick Answer

HTTP 404 Not Found means the server cannot find the requested resource. The URL may be wrong, the resource may have been deleted, or it was never published.

Why HTTP 404 Occurs

HTTP 404 Not Found means the server cannot find the requested URL. Common causes: typo in the URL, resource was deleted, URL changed and no redirect was set up, dynamic routes not matched (missing slug), case-sensitive URL mismatch, and trailing slash differences (/users vs /users/). In Next.js, return notFound() from a page or API route to generate a 404. In Express: if no route matches, the default behavior is a 404 response.

Handling 404 in Code

Express.js catch-all 404: app.use((req, res) => { res.status(404).json({ error: "Not found" }); }). Next.js: create app/not-found.tsx for a custom 404 page. For API routes, call notFound() from next/navigation. In fetch(): const res = await fetch(url); if (res.status === 404) { /* handle missing resource */ }. Never cache a 404 without a short TTL - resources may be created later. For deleted resources, prefer 410 Gone.

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Frequently Asked Questions

Related Values

100

HTTP 100 Continue means the server has received the request headers and the client should proceed to send the request body. It is an interim response used to inform the client to continue.

101

HTTP 101 Switching Protocols indicates the server is switching to the protocol specified in the Upgrade header field. Commonly used when upgrading to WebSocket connections.

200

HTTP 200 OK is the standard success response. The request has succeeded and the server has returned the requested resource in the response body.

201

HTTP 201 Created means the request succeeded and a new resource was created as a result. The Location header typically points to the new resource URL.