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?
Cloudflare could not connect to the origin at all — refused, offline, or wrong port.
When to use
Origin process not listening. Contrast with 522 (connect timeout).
Don’t
Not an origin status. The origin equivalent is “connection refused.”
Live URL
curl -i https://corecoding.com/utilities/http-status.php?code=521
No codes match.
Code use cases