# Programmatic testing of TwiML Bins

If you want to programmatically test your TwiML Bins, you'll have to generate a valid `X-Twilio-Signature` using your Account SID and Auth Token, and then make an HTTP request to your TwiML Bin URL that contains:

1. The `X-Twilio-Signature` HTTP header
2. The `AccountSid` either as a query parameter or `POST` body parameter

## Generating the X-Twilio-Signature

Some of our SDKs provide you with the ability to generate an `X-Twilio-Signature` to verify that a webhook request comes from your Twilio account. You can use the same tooling to generate a valid `X-Twilio-Signature`. For example, in Node.js this would look like:

```js
const webhooks = require('twilio/lib/webhooks/webhooks');
const eventData = {
  AccountSid: accountSid,
}
const signature = webhooks.getExpectedTwilioSignature(
  authToken,
  url,
  eventData
);
```

Using this data, you can then make your HTTP request successfully, as long as you pass an `X-Twilio-Signature` HTTP header and the same data in the `POST` body that you passed to the `eventData` object of the `getExpectedTwilioSignature()` function.

## Example

Here's a full example in Node.js that makes an HTTP request using Axios to a TwiML Bin URL, and compares the result against the expected result.

```js
const webhooks = require('twilio/lib/webhooks/webhooks');
const { default: axios } = require('axios');
const assert = require('assert');

async function makeTwiMLBinRequest(url, data) {
  // Get account credentials from your environment variables
  const accountSid = process.env.TWILIO_ACCOUNT_SID;
  const authToken = process.env.TWILIO_AUTH_TOKEN;

  const eventData = {
    AccountSid: accountSid,
    ...data
  }

  // Construct a valid application/x-www-form-urlencoded POST body
  const params = new URLSearchParams();
  for (const [key, value] of Object.entries(eventData)) {
    params.append(key, value);
  }
  data = params.toString();

  // Generate the X-Twilio-Signature
  const signature = webhooks.getExpectedTwilioSignature(
    authToken,
    url,
    eventData
  );
  const headers = {};
  headers['X-Twilio-Signature'] = signature;

  // Make the HTTP request to the passed URL
  const response = await axios.request({
    method: 'POST',
    headers,
    url,
    data
  })
  return response.data;
}

// Make an HTTP request to your TwiML Bin
const response = await makeTwiMLBinRequest('https://handler.twilio.com/twiml/EHaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa', { Body: 'Hello' })

// Compare the output against your expected result
assert.deepEqual(response, `<?xml version="1.0" encoding="UTF-8"?>
<Response>
  <Message>Ahoy</Message>
</Response>`);
```