Mock XML endpoint returning HTTP 504

Live demo endpoint

Any method, any path. Returns 504 Gateway Timeout with Content-Type: application/xml. OPTIONS returns 204 with CORS headers.

Call it with curl

curl -i https://demo-xml-504.supercrontab.com/

Call it with fetch

const res = await fetch("https://demo-xml-504.supercrontab.com/");
console.log(res.status); // 504
const body = await res.text();

What HTTP 504 Gateway Timeout means

When you see it

A proxy waited for the upstream app and gave up. The request may or may not have been processed.

What a client should do

Retry only idempotent requests, with backoff. For POSTs use an idempotency key so a retry cannot double-apply.

Retry?

Yes, with backoff

Sample response body

<?xml version="1.0" encoding="UTF-8"?>
<response>
  <ok>true</ok>
  <id>42</id>
</response>

Common in SOAP, payment and legacy enterprise APIs. Good for testing XML parsers and namespaces.

Questions