Buy a number and configure inbound trunk

You understand how phone calls flow through SIP into LiveKit rooms. Now it is time to get a real phone number and wire it up. By the end of this chapter, you will have a phone number that routes incoming calls to LiveKit's SIP bridge -- the first half of the connection between the phone network and your dental receptionist agent.

What you'll learn

• How to get a phone number through LiveKit Cloud, Twilio, or Telnyx
• What a SIP trunk is and why you need one
• How to create an inbound SIP trunk via the CLI
• How to create an inbound SIP trunk programmatically in Python and TypeScript

Getting a phone number

You need a phone number that the public can dial. There are three paths, and all lead to the same result: a number whose calls arrive at LiveKit's SIP bridge.

Option 1: LiveKit Cloud phone numbers (simplest)

LiveKit Cloud can provision phone numbers directly. This is the fastest path because the number is automatically configured to route to LiveKit's SIP bridge -- no third-party account needed.

# List available numbers in a region
lk sip phone list-available --area-code 415

# Purchase a number
lk sip phone purchase --number "+14155551234"

Option 2: Twilio

If you already have a Twilio account or need features like international numbers in many countries, you can use Twilio as your trunk provider.

Option 3: Telnyx

Telnyx is another popular SIP trunk provider with competitive per-minute pricing and good global coverage.

What is an inbound SIP trunk?

A SIP trunk is the configuration object in LiveKit that says: "I expect incoming SIP calls on these phone numbers. Accept them." It is the handshake between your trunk provider and LiveKit's SIP bridge.

An inbound trunk stores:

• Name -- a human-readable label (e.g., "Dental Office Inbound")
• Numbers -- the phone numbers associated with this trunk (E.164 format)
• Authentication -- optional credentials or IP allowlists to restrict who can send SIP traffic
• Trunk ID -- an auto-generated identifier (e.g., ST_xxxxxxxxxxxx) used to reference the trunk in dispatch rules

Creating an inbound trunk via CLI

The fastest way to create an inbound trunk is with the LiveKit CLI:

lk sip trunk create --name "Dental Office" --numbers "+15551234567"

This returns a trunk object with an ID like ST_xxxxxxxxxxxx. Save this ID -- you will need it in the next chapter when configuring dispatch rules.

You can verify the trunk was created:

lk sip trunk list

Creating an inbound trunk via the API

For production systems, you will typically create trunks programmatically as part of your provisioning workflow. Here is how to do it in both Python and TypeScript.

Python

import asyncio
from livekit.api import LiveKitAPI, CreateSIPInboundTrunkRequest, SIPInboundTrunkInfo


async def main():
  api = LiveKitAPI()

  trunk = await api.sip.create_sip_inbound_trunk(
      CreateSIPInboundTrunkRequest(
          trunk=SIPInboundTrunkInfo(
              name="Dental Office Inbound",
              numbers=["+15551234567"],
          )
      )
  )

  print(f"Created trunk: {trunk.sip_trunk_id}")
  print(f"Name: {trunk.name}")
  print(f"Numbers: {trunk.numbers}")

  await api.aclose()


asyncio.run(main())

TypeScript

import { SipClient } from "livekit-server-sdk";

const sipClient = new SipClient(
process.env.LIVEKIT_URL!,
process.env.LIVEKIT_API_KEY!,
process.env.LIVEKIT_API_SECRET!
);

const trunk = await sipClient.createSipInboundTrunk({
name: "Dental Office Inbound",
numbers: ["+15551234567"],
});

console.log(`Created trunk: ${trunk.sipTrunkId}`);
console.log(`Name: ${trunk.name}`);
console.log(`Numbers: ${trunk.numbers}`);

Listing and managing trunks

Once created, you can list all trunks in your project:

import asyncio
from livekit.api import LiveKitAPI, ListSIPInboundTrunkRequest


async def main():
  api = LiveKitAPI()

  response = await api.sip.list_sip_inbound_trunk(
      ListSIPInboundTrunkRequest()
  )

  for trunk in response.items:
      print(f"{trunk.sip_trunk_id}: {trunk.name} ({trunk.numbers})")

  await api.aclose()


asyncio.run(main())

import { SipClient } from "livekit-server-sdk";

const sipClient = new SipClient(
process.env.LIVEKIT_URL!,
process.env.LIVEKIT_API_KEY!,
process.env.LIVEKIT_API_SECRET!
);

const trunks = await sipClient.listSipInboundTrunk();

for (const trunk of trunks) {
console.log(`${trunk.sipTrunkId}: ${trunk.name} (${trunk.numbers})`);
}

What you learned

• You can get a phone number through LiveKit Cloud (simplest), Twilio, or Telnyx
• An inbound SIP trunk tells LiveKit to accept incoming calls on specific phone numbers
• Trunks are created with the lk sip trunk create CLI command or the CreateSIPInboundTrunkRequest API
• Each trunk gets a unique ID (ST_xxxxxxxxxxxx) used to link it to dispatch rules
• Trunks can be managed programmatically for production provisioning workflows

Next up

You have a phone number and an inbound trunk, but LiveKit does not yet know what to do when a call arrives. In the next chapter, you will configure dispatch rules that route incoming calls to your dental receptionist agent.