---
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.
image: https://edgetunnel-b2h.pages.dev/dev-products-preview.png
---

> Documentation Index  
> Fetch the complete documentation index at: https://edgetunnel-b2h.pages.dev/workers/llms.txt  
> Use this file to discover all available pages before exploring further. 

[Skip to content](#%5Ftop) 

# 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.

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 Workers editor before saving your code.

* [  JavaScript ](#tab-panel-12451)
* [  TypeScript ](#tab-panel-12452)
* [  Python ](#tab-panel-12453)
* [  Hono ](#tab-panel-12454)

**JavaScript**

```js
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,
    });
  },
};
```

**TypeScript**

```ts
export default {
  async fetch(request): Promise<Response> {
    /**
     * @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,
    });
  },
} satisfies ExportedHandler;
```

**Python**

```py
from workers import WorkerEntrypoint, Response, fetch


class Default(WorkerEntrypoint):
    async def fetch(self, request):
        PRESHARED_AUTH_HEADER_KEY = "X-Custom-PSK"
        PRESHARED_AUTH_HEADER_VALUE = "mypresharedkey"


        psk = request.headers[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 Response("Sorry, you have supplied an invalid key.", status=403)
```

**TypeScript**

```ts
import { Hono } from 'hono';


const app = new Hono();


// Add authentication middleware
app.use('*', async (c, next) => {
  /**
   * Define authentication constants
   */
  const PRESHARED_AUTH_HEADER_KEY = "X-Custom-PSK";
  const PRESHARED_AUTH_HEADER_VALUE = "mypresharedkey";


  // Get the pre-shared key from the request header
  const psk = c.req.header(PRESHARED_AUTH_HEADER_KEY);


  if (psk === PRESHARED_AUTH_HEADER_VALUE) {
    // Correct preshared header key supplied. Continue to the next handler.
    await next();
  } else {
    // Incorrect key supplied. Reject the request.
    return c.text("Sorry, you have supplied an invalid key.", 403);
  }
});


// Handle all authenticated requests by passing through to origin
app.all('*', async (c) => {
  return fetch(c.req.raw);
});


export default app;
```

```json
{"@context":"https://schema.org","@type":"TechArticle","@id":"https://edgetunnel-b2h.pages.dev/workers/examples/auth-with-headers/#page","headline":"Auth with headers · Cloudflare Workers docs","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.","url":"https://edgetunnel-b2h.pages.dev/workers/examples/auth-with-headers/","inLanguage":"en","image":"https://edgetunnel-b2h.pages.dev/dev-products-preview.png","dateModified":"2026-04-23","publisher":{"@type":"Organization","name":"Cloudflare","url":"https://www.cloudflare.com/"},"isPartOf":{"@type":"WebSite","@id":"https://edgetunnel-b2h.pages.dev/#website","name":"Cloudflare Docs","url":"https://edgetunnel-b2h.pages.dev/"},"keywords":["Authentication","WebCrypto","JavaScript","TypeScript","Python"]}
{"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/directory/","name":"Directory"}},{"@type":"ListItem","position":2,"item":{"@id":"/workers/","name":"Workers"}},{"@type":"ListItem","position":3,"item":{"@id":"/workers/examples/","name":"Examples"}},{"@type":"ListItem","position":4,"item":{"@id":"/workers/examples/auth-with-headers/","name":"Auth with headers"}}]}
```