---
title: Auth with headers
description: Allow or deny a request based on a known pre-shared key in a header. This is not meant to replace the [WebCrypto API](/workers/runtime-apis/web-crypto/).
image: https://developers.cloudflare.com/core-services-preview.png
---

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# Auth with headers

Allow or deny a request based on a known pre-shared key in a header. This is not meant to replace the [WebCrypto API](https://developers.cloudflare.com/workers/runtime-apis/web-crypto/).

Caution when using in production

The example code contains a generic header key and value of `X-Custom-PSK` and `mypresharedkey`. To best protect your resources, change the header key and value in the Snippets editor before saving your code.

JavaScript

```
export default {  async fetch(request) {    /**     * @param {string} PRESHARED_AUTH_HEADER_KEY Custom header to check for key     * @param {string} PRESHARED_AUTH_HEADER_VALUE Hard-coded key value     */    const PRESHARED_AUTH_HEADER_KEY = "X-Custom-PSK";    const PRESHARED_AUTH_HEADER_VALUE = "mypresharedkey";    const psk = request.headers.get(PRESHARED_AUTH_HEADER_KEY);
    if (psk === PRESHARED_AUTH_HEADER_VALUE) {      // Correct preshared header key supplied. Fetch request from origin.      return fetch(request);    }
    // Incorrect key supplied. Reject the request.    return new Response("Sorry, you have supplied an invalid key.", {      status: 403,    });  },};
```

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