# Signature verification

If you want to make sure a WebHook received by your platform has been sent by the Xumm platform, verify the signature the platform sends in an HTTP header.

Every WebHook call contains a signature to verify the authenticity. It sends an HMAC using your application secret as a key. Sample verification in NodeJS:

```javascript
import crypto from 'crypto'

// Xumm App secret (Xumm developer console)
const secret = 'xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx'

const timestamp = req.headers?.['x-xumm-request-timestamp'] || ''
const json = req.body

const hmac = crypto.createHmac('sha1', secret.replace('-', ''))
  .update(timestamp + JSON.stringify(json))
  .digest('hex')

console.log(hmac, hmac === req.headers?.['x-xumm-request-signature'])
```


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# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.xaman.dev/concepts/payloads-sign-requests/status-updates/webhooks/signature-verification.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.