Rest-apiConceptBeginner · 3 min read

What is 404 Status Code: Meaning and Usage in REST APIs

The 404 status code means "Not Found" in HTTP responses. It tells the client that the requested resource does not exist on the server.

⚙️

How It Works

Imagine you are looking for a book in a library, but the librarian tells you the book is not on the shelves. In web terms, when you ask a server for a webpage or data that isn't there, the server replies with a 404 status code. This code is part of the HTTP response and signals that the resource you requested cannot be found.

This helps the client (like a web browser or app) understand that the address or link they used is wrong or the resource was removed. It’s a clear way for servers to say, "Sorry, we don’t have what you asked for." This prevents confusion and helps users or programs handle missing pages gracefully.

💻

Example

This example shows a simple HTTP server in Python that returns a 404 status code when a requested page is not found.

python

from http.server import BaseHTTPRequestHandler, HTTPServer

class SimpleHandler(BaseHTTPRequestHandler):
    def do_GET(self):
        if self.path == '/':
            self.send_response(200)
            self.send_header('Content-type', 'text/html')
            self.end_headers()
            self.wfile.write(b"<html><body><h1>Home Page</h1></body></html>")
        else:
            self.send_response(404)
            self.send_header('Content-type', 'text/html')
            self.end_headers()
            self.wfile.write(b"<html><body><h1>404 Not Found</h1></body></html>")

if __name__ == '__main__':
    server = HTTPServer(('localhost', 8000), SimpleHandler)
    print('Server running on http://localhost:8000')
    server.serve_forever()

Output

Server running on http://localhost:8000

🎯

When to Use

Use the 404 status code whenever a client requests a resource that does not exist on your server. For example:

If a user types a wrong URL or clicks a broken link.
If a requested file or page was deleted or moved.
When an API client asks for data that is not available.

Returning a 404 helps users and programs know the resource is missing instead of failing silently or showing incorrect data. It also improves user experience by allowing websites to show helpful "Page Not Found" messages.

✅

Key Points

404 means the requested resource was not found on the server.
It is part of the HTTP response status codes used in REST APIs and websites.
Helps clients understand that the URL or resource is invalid or missing.
Commonly used for broken links, deleted pages, or wrong URLs.
Improves user experience by enabling custom "Not Found" pages.

✅

Key Takeaways

The 404 status code means the requested resource was not found on the server.

Use 404 to clearly indicate missing pages or data in web and API responses.

It helps clients handle errors gracefully and improves user experience.

Always return 404 instead of a generic error when a resource is missing.

Custom 404 pages can guide users back to valid content.