---
description: Use the cf-mitigated header to identify challenge page responses in fetch and XHR requests.
title: Detect a Challenge Page response
image: https://developers.cloudflare.com/og-docs.png
---

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# Detect a Challenge Page response

Last updated Aug 24, 2026|Copy as Markdown|[View as Markdown](https://docs-durable-objects-instance-replaced-errors.previews.developers.cloudflare.com/cloudflare-challenges/challenge-types/challenge-pages/detect-response/index.md)|[Agent setup](https://docs-durable-objects-instance-replaced-errors.previews.developers.cloudflare.com/agent-setup/)

When a request encounters a Cloudflare Challenge Page instead of the originally anticipated response, the Challenge Page response (regardless of the Challenge Page type) will have the `cf-mitigated` header present and set to `challenge`. This header can be leveraged to detect if a response was challenged when making fetch/XHR requests. This header provides a reliable way to identify whether a response is a Challenge or not, enabling a web application to take appropriate action based on the result. For example, a front-end application encountering a response from the backend may check the presence of this header value to handle cases where Challenge Pages encountered unexpectedly.

Note

Regardless of the requested resource-type, the content-type of a challenge will be `text/html`.

For the `cf-mitigated` header, `challenge` is the only valid value. The header is set for all Challenge Page types.

To illustrate, here is a JavaScript code snippet that demonstrates how to use the `cf-mitigated` header to detect whether a response was challenged:

```js
fetch("/my-api-endpoint").then((response) => {
	if (response.headers.get("cf-mitigated") === "challenge") {
		// Handle challenged response
	} else {
		// Process response as usual
	}
});
```

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