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HTTP Status Code
404 Not Found
Client ErrorThe server could not find the requested resource.
HTTP status code reference, response example, common causes, fixes, and related status codes.
What does HTTP 404 Not Found mean?
HTTP 404 Not Found is a status code sent by a server to indicate the result of an HTTP request.
Status codes help browsers, APIs, apps, and backend systems understand whether a request succeeded, failed, was redirected, or needs additional action.
In practice, HTTP 404 Not Found usually appears when a server responds under specific request, validation, permission, or infrastructure conditions.
Response example
HTTP/1.1 404 Not Found
HTTP example
HTTP/1.1 404 Not Found
Common causes
- Broken link
- Deleted page
- Wrong endpoint URL
- Invalid route parameter
How to fix it
- Check the URL
- Verify the route exists
- Update broken internal links
Common mistakes
- Assuming the status code alone explains the full backend issue
- Ignoring related response headers that add important context
- Treating temporary errors as permanent failures
- Retrying too aggressively without checking the cause
- Debugging the frontend only when the problem is server-side
How browsers and APIs use it
Browsers, APIs, and backend services use HTTP status codes to understand the outcome of a request. Depending on the status code, an application may render content, retry a request, redirect the user, show an error, or trigger a different flow in the client or server.
Developer note
HTTP 404 is one of the most common web errors. In apps, it often means the route is wrong or the requested item no longer exists.
Client-side example
if (response.status === 404) {
console.log("Resource not found");
}