twilio-conference-calls

Overview

Conference is the foundation of contact center call handling. The key insight: every call that might need a transfer should start as a Conference, not a direct <Dial>. A Conference supports hold, transfer, coaching, and recording — a direct Dial does not.

Caller ──→ Conference Room ←── Agent
                  ↑
              Supervisor (coach mode: speaks to agent only)

Contact center best practice: Every multi-agent call should use Conference, not direct Dial.

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Prerequisites

• Twilio account with a voice-capable phone number — see twilio-account-setup
• TWILIO_ACCOUNT_SID and TWILIO_AUTH_TOKEN — see twilio-iam-auth-setup
• SDK: pip install twilio / npm install twilio
• For agent routing: TaskRouter — see twilio-taskrouter-routing

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Quickstart

Step 1 — Put the inbound caller into a Conference

When a call comes in, place the caller into a named Conference room.

Python (Flask)

from flask import Flask, request
from twilio.twiml.voice_response import VoiceResponse

app = Flask(__name__)

@app.route("/voice", methods=["POST"])
def incoming_call():
    call_sid = request.form["CallSid"]
    response = VoiceResponse()
    dial = response.dial()
    dial.conference(
        f"room-{call_sid}",
        start_conference_on_enter=True,
        end_conference_on_exit=False,  # Keep conference alive when caller disconnects (for wrap-up)
        wait_url="http://twimlets.com/holdmusic?Bucket=com.twilio.music.classical",
        status_callback="https://yourapp.com/conference-events",
        status_callback_event="join leave",
        record="record-from-start"
    )
    return str(response)

Node.js (Express)

app.post("/voice", (req, res) => {
    const callSid = req.body.CallSid;
    const response = new VoiceResponse();
    const dial = response.dial();
    dial.conference(
        `room-${callSid}`,
        {
            startConferenceOnEnter: true,
            endConferenceOnExit: false,
            waitUrl: "http://twimlets.com/holdmusic?Bucket=com.twilio.music.classical",
            statusCallback: "https://yourapp.com/conference-events",
            statusCallbackEvent: "join leave",
            record: "record-from-start",
        }
    );
    res.type("text/xml").send(response.toString());
});