Rooms Are Great. Calls Need a Phone Company.

LiveKit is a strong WebRTC media server for video and audio rooms. Phone calls require native SIP, PSTN, and call transfers that a room-based architecture cannot provide.

A Room Is Not a Call

Two platforms for one phone call

LiveKit handles the room. Twilio handles the phone line. Two platforms means two bills, two failure domains, and two sets of logs with no shared trace ID.

SIP bridge adds latency and failure modes

Bridging a SIP trunk into a WebRTC room introduces another hop and a single point of failure with limited error visibility.

Transfers break across room boundaries

Cold transfers and voice-triggered transfers fail across room boundaries. Call transfers are fundamental telephony operations, not edge cases.

IMS carriers expose protocol gaps

Session timers, re-INVITEs, and QoS preconditions expose gaps when room abstractions meet real carrier infrastructure.

Build a Voice AI Agent

from signalwire import AgentBase
from signalwire.core.function_result import FunctionResult

class SupportAgent(AgentBase):
    def __init__(self):
        super().__init__(name="Support Agent", route="/support")
        self.prompt_add_section("Instructions",
            body="You are a customer support agent. "
                 "Greet the caller and resolve their issue.")
        self.add_language("English", "en-US", "rime.spore:mistv2")

@AgentBase.tool(name="check_order")
    def check_order(self, order_id: str):
        """Check the status of a customer order.
        Args:
            order_id: The order ID to look up
        """
        return FunctionResult(f"Order {order_id}: shipped, ETA April 2nd")

agent = SupportAgent()
agent.run()

Two Platforms vs. One Platform

LiveKit + Twilio

A room server and phone provider must coordinate every call.

SignalWire

Native SIP, PSTN, media, and AI in one engine. Call state remains authoritative throughout the lifecycle. One trace covers telephony and AI behavior.

Migrate From LiveKit + Twilio to One Platform

Install the SDK

Install signalwire-agents and connect the same business logic to a telephony-native agent.

Define your agent in YAML or Python

Move prompts, tools, and conversation rules without rebuilding the underlying telephony stack.

Point a phone number at your agent

Provision or port numbers and route calls directly to the agent.

Test transfers and call flows

Validate native transfers, SIP behavior, and end-to-end latency with real phone traffic.

Sigmond Runs on SignalWire

A voice and video AI agent built on the SignalWire SDK, wired to a live knowledge base, able to see what you show him. Build the same thing on voice, phone, WhatsApp, or SIP, or an entire white-label platform with SignalWire as the network underneath.

Stop bridging. Start calling.

Deploy voice AI agents on native telephony with sub-second latency and global phone numbers.