501 Not Implemented

Look up a status, pick the right one for an API, or hit a live endpoint that actually returns it. Add ?code=418 to this URL and the response is that status — useful for curl, interceptors, and “what does my client do on 503?” Nothing here phones home except the Try it fetch to this same page.

Which class?

501

Not Implemented

Server error · RFC 9110

The server does not support the functionality. Usually an unknown method at this origin.

When to use

HTTP method the origin will never support. “Coming soon” endpoints.

Don’t

This resource exists but not this method: 405. Unknown URL: 404.

Live URL

curl -i https://corecoding.com/utilities/http-status.php?code=501


    

Code use cases