Mock HTML endpoint returning HTTP 502

https://demo-html-502.supercrontab.com/ answers every request with HTTP 502 Bad Gateway and a small HTML body. No signup, CORS enabled, nothing logged. Use it to see how your client, retry logic or cron job behaves on a 502 before it happens in production.

Live demo endpoint

https://demo-html-502.supercrontab.com/

Any method, any path. Returns 502 Bad Gateway with Content-Type: text/html; charset=utf-8. OPTIONS returns 204 with CORS headers.

Call it with curl

curl -i https://demo-html-502.supercrontab.com/

Call it with fetch

const res = await fetch("https://demo-html-502.supercrontab.com/");
console.log(res.status); // 502
const body = await res.text();

What HTTP 502 Bad Gateway means

When you see it: A proxy or load balancer got an invalid response from the upstream app, often during a deploy or a crash.
What a client should do: Retry with exponential backoff. Deploys usually finish within a minute, so a few retries are enough.
Retry?: Yes, with backoff

Sample response body

<!doctype html>
<html>
  <head><title>Mock page</title></head>
  <body><h1>ok</h1><p>id 42</p></body>
</html>

A tiny page. Useful for scrapers, uptime monitors and testing how a client treats HTML error pages.

Questions

Does this endpoint really return HTTP 502 every time?

Yes. Every GET, POST, PUT, PATCH or DELETE to https://demo-html-502.supercrontab.com/ gets status 502 Bad Gateway with a small HTML body, whatever the path, query or headers. OPTIONS gets 204 with CORS headers so browsers can preflight.

Should my client retry a 502?

Yes, with exponential backoff and a cap on attempts. Retry with exponential backoff. Deploys usually finish within a minute, so a few retries are enough.

Can I get a different format, a delay or a custom body?

The same status is available in JSON, XML, Text, CSV, YAML, RSS, JavaScript. Delays, custom headers, error rates, request logging and your own body need a personal endpoint: sign up and create one at /endpoints in a minute, free.