Hey guys! If my assistant triggers a tool during a call, and the tool has a webhook sent to my Make.com scenario - In that webhook output I see a listenURL field. Can I use that URL to get the mp3 of the call that is ongoing? I mean like a real-time "what has happened so far in the call" kind of thing. I could not open the url afterwards to test it because after the call it is labelled as expired.

You can use the

listenUrl

from the webhook to stream the call's audio in real-time, but only while the call is ongoing. The stream is in raw PCM format, not MP3, and the URL expires after the call ends. Here’s a Node.js example to save the audio during the call:

js
const WebSocket = require('ws');
const fs = require('fs');
let pcmBuffer = Buffer.alloc(0);
const ws = new WebSocket('wss://your-listen-url-here');
ws.on('message', (data, isBinary) => {
  if (isBinary) pcmBuffer = Buffer.concat([pcmBuffer, data]);
});
ws.on('close', () => fs.writeFileSync('audio.pcm', pcmBuffer));

Connect to the

listenUrl

during the call to capture audio; you cannot access it after the call ends. Source: - [Call Listen Feature – Vapi Documentation](https://docs.vapi.ai/calls/call-features#call-listen-feature)

Yes, the listenUrl is a WebSocket that streams live call audio in real-time, but it only works during the active call, once the call ends, the URL expires and cannot be used to access past audio.