xAI Voice Agents Integration

Build a Grok voice-agent in xAI Voice Agents and have it answer calls to your Plivo phone number. Plivo sends each call over an inbound SIP trunk to xAI, where the agent is hosted, so you don’t run any server.

How the integration works

Call flowPlivo SIP Trunking · xAI

CallerDials your Plivo phone number
Plivo inbound SIP trunkPrimary URI: sip.voice.x.ai
SIP over TLS
xAIChecks Plivo’s IP address or SIP digest credentials, then matches the dialed number
xAI Voice AgentAnswers with its welcome message

Step	What happens	Where you configure it
1	A caller dials your Plivo phone number.	Plivo number connected to an inbound trunk
2	Plivo sends the call over the inbound SIP trunk to `sip.voice.x.ai` using TLS.	Plivo inbound trunk
3	xAI accepts the call from Plivo’s IP addresses (or SIP digest credentials) and matches the dialed number to your agent.	Phone number in your xAI agent
4	The agent answers with its saved instructions, voice, and welcome message.	xAI Console → Voice Agents

Inbound only: xAI Voice Agents answer incoming calls. They don’t place outbound calls. See Outbound calls.

Prerequisites

Requirement	Description
Plivo Account	Sign up with SIP trunking enabled
Phone Number	Purchase a voice-enabled number
xAI Account	An account in the xAI Console with access to Voice Agents

For the code samples, you also need:

Your Plivo Auth ID and Auth Token, available on the Plivo Console home page. The Plivo API uses HTTP Basic authentication.
An xAI API key, created on the API Keys page of the xAI Console. The xAI API uses Bearer authentication.
The Plivo CLI, logged in with plivo login. The CLI uses the profile saved by plivo login, not the environment variables below.

Export your credentials as environment variables to use with the cURL, Python, and Node samples:

export PLIVO_AUTH_ID="<your_auth_id>"
export PLIVO_AUTH_TOKEN="<your_auth_token>"
export XAI_API_KEY="<your_xai_api_key>"

Inbound calls

Set up the agent in xAI, route your Plivo number to xAI, and then connect the number to the agent.

Create a voice agent in the xAI Console

Create the agent in the xAI Console. xAI doesn’t provide APIs to create or manage voice agents.

Sign in to the xAI Console and select Voice Agents in the left navigation.
Select Create agent. A builder chat asks about your use case. Describe it, or select Skip to configure the agent yourself.
Alternatively, select a template (such as Customer Support or Appointment Scheduler) or Start from scratch from the agents list. The agent is created as soon as you select one.
To rename the agent, select the pencil icon next to its name, enter a Name, and select Save.

Copy the agent ID from the page URL, for example agent_a1B2c3D4e5F6g7H8.

Configure and publish the agent

On the Configuration tab, enter the agent’s Instructions.
Turn on Welcome message and enter a greeting to have the agent speak first. When it’s off, the agent waits for the caller to speak.
Optional: review the settings that matter on a phone call:

Setting	Tab	What it does
Caller can interrupt	Configuration	Lets caller speech interrupt the welcome message.
Know caller’s phone number	Configuration	Lets the agent see and use the caller’s phone number during the call.
Voice	Speech	Selects a built-in or custom voice.
Language	Speech	Improves recognition when callers speak a specific language. The default is Auto-detect.
Follow-up after silence	Speech	Prompts callers when they go quiet.

Select Publish.

Publish after every change: Edits are saved as a draft, and the agent’s status changes from Live to Draft. Calls use the published version until you select Publish again.

Create an inbound trunk in Plivo

Create an inbound trunk that sends calls to xAI’s SIP endpoint, sip.voice.x.ai, over TLS.

Console
API

Sign in to the Plivo Console.
Navigate to SIP Trunking → Inbound Trunks and select Create Trunk.
Enter a Trunk Name, for example xAI-Inbound.
For SIP Platform, select xAI (SpaceXAI). The Primary URI is filled in with the xAI SIP URI, sip:sip.voice.x.ai;transport=tls.
Select Create Trunk.

First, create an origination URI that points to xAI’s SIP endpoint over TLS:

plivo sip uris create --name xAI-Primary --uri "sip.voice.x.ai;transport=tls"

curl "https://api.plivo.com/v1/Account/$PLIVO_AUTH_ID/Zentrunk/URI/" \
-u "$PLIVO_AUTH_ID:$PLIVO_AUTH_TOKEN" \
-H 'Content-Type: application/json' \
-d '{
  "name": "xAI-Primary",
  "uri": "sip.voice.x.ai;transport=tls"
}'

import os
import requests

auth_id = os.environ["PLIVO_AUTH_ID"]
auth_token = os.environ["PLIVO_AUTH_TOKEN"]

response = requests.post(
    f"https://api.plivo.com/v1/Account/{auth_id}/Zentrunk/URI/",
    auth=(auth_id, auth_token),
    json={
        "name": "xAI-Primary",
        "uri": "sip.voice.x.ai;transport=tls",
    },
)
print(response.json())

const authId = process.env.PLIVO_AUTH_ID;
const authToken = process.env.PLIVO_AUTH_TOKEN;
const authHeader = 'Basic ' + Buffer.from(`${authId}:${authToken}`).toString('base64');

const response = await fetch(`https://api.plivo.com/v1/Account/${authId}/Zentrunk/URI/`, {
  method: 'POST',
  headers: {
    'Authorization': authHeader,
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    name: 'xAI-Primary',
    uri: 'sip.voice.x.ai;transport=tls',
  }),
});
console.log(await response.json());

Copy the uri_uuid from the response for the next request:

{
  "api_id": "<api_id>",
  "message": "Origination URI created successfully",
  "uri_uuid": "<uri_uuid>"
}

Then create an inbound trunk that uses the URI as its primary URI:

plivo sip trunks create --name xAI-Inbound --direction inbound --uri <uri_uuid>

curl "https://api.plivo.com/v1/Account/$PLIVO_AUTH_ID/Zentrunk/Trunk/" \
-u "$PLIVO_AUTH_ID:$PLIVO_AUTH_TOKEN" \
-H 'Content-Type: application/json' \
-d '{
  "name": "xAI-Inbound",
  "trunk_direction": "inbound",
  "primary_uri_uuid": "<uri_uuid>"
}'

import os
import requests

auth_id = os.environ["PLIVO_AUTH_ID"]
auth_token = os.environ["PLIVO_AUTH_TOKEN"]

response = requests.post(
    f"https://api.plivo.com/v1/Account/{auth_id}/Zentrunk/Trunk/",
    auth=(auth_id, auth_token),
    json={
        "name": "xAI-Inbound",
        "trunk_direction": "inbound",
        "primary_uri_uuid": "<uri_uuid>",
    },
)
print(response.json())

const authId = process.env.PLIVO_AUTH_ID;
const authToken = process.env.PLIVO_AUTH_TOKEN;
const authHeader = 'Basic ' + Buffer.from(`${authId}:${authToken}`).toString('base64');

const response = await fetch(`https://api.plivo.com/v1/Account/${authId}/Zentrunk/Trunk/`, {
  method: 'POST',
  headers: {
    'Authorization': authHeader,
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    name: 'xAI-Inbound',
    trunk_direction: 'inbound',
    primary_uri_uuid: '<uri_uuid>',
  }),
});
console.log(await response.json());

Copy the trunk_id from the response for the next step:

{
  "api_id": "<api_id>",
  "message": "Trunk created successfully.",
  "trunk_id": "<trunk_id>"
}

Connect your phone number

Route calls to your Plivo phone number through the inbound trunk.

Console
API

Navigate to Phone Numbers and select your phone number.
For Application Type, select SIP Trunk.
For SIP Inbound Trunk, select the trunk you created in the previous step.
Select Save changes.

Assign the inbound trunk to your phone number using the update a number endpoint. Set app_id to the trunk ID of your inbound trunk. Use your phone number in E.164 format without the leading +, for example 15105550100:

plivo numbers update 15105550100 --trunk-id <trunk_id>

curl "https://api.plivo.com/v1/Account/$PLIVO_AUTH_ID/Number/15105550100/" \
-u "$PLIVO_AUTH_ID:$PLIVO_AUTH_TOKEN" \
-H 'Content-Type: application/json' \
-d '{
  "app_id": "<trunk_id>"
}'

import os
import requests

auth_id = os.environ["PLIVO_AUTH_ID"]
auth_token = os.environ["PLIVO_AUTH_TOKEN"]
phone_number = "15105550100"

response = requests.post(
    f"https://api.plivo.com/v1/Account/{auth_id}/Number/{phone_number}/",
    auth=(auth_id, auth_token),
    json={
        "app_id": "<trunk_id>",
    },
)
print(response.json())

const authId = process.env.PLIVO_AUTH_ID;
const authToken = process.env.PLIVO_AUTH_TOKEN;
const authHeader = 'Basic ' + Buffer.from(`${authId}:${authToken}`).toString('base64');
const phoneNumber = '15105550100';

const response = await fetch(`https://api.plivo.com/v1/Account/${authId}/Number/${phoneNumber}/`, {
  method: 'POST',
  headers: {
    'Authorization': authHeader,
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    app_id: '<trunk_id>',
  }),
});
console.log(await response.json());

A successful response returns HTTP 202:

{
  "api_id": "<api_id>",
  "message": "changed"
}

Assign the number to your agent

Add your Plivo phone number to the agent, and allow all of Plivo’s signaling IP addresses. xAI accepts calls for the number only from these ranges, and Plivo can route a call through any region during a service disruption:

52.9.0/25
120.187.128/26
214.109.128/25
215.142.0/26
89.148.128/26
120.121.128/26
228.70.64/26
233.191.0/27
238.202.192/26
136.1.128/26
89.149.128/27
207.90.192/31
89.151.128/27
89.151.160/27

To authenticate Plivo with a SIP username and password instead, see Use SIP digest authentication.

Console
API

In the xAI Console, open your agent and select the Deployment tab.
Under Phone numbers, select Add number.
Select Direct SIP. You’re connecting your own Plivo number, so you don’t need a phone number from xAI. If the dialog says xAI can’t provision numbers in your region, you can continue.
Enter a Name and your Phone number in E.164 format, for example +15105550100.
Under Allowed addresses, enter each IP address range from the list above, and select Add after each one.
Select Add number.

Add the ranges faster: The field accepts one range at a time. Press Enter after each range instead of selecting Add. To add all 14 ranges in a single request, use the API tab instead.

The number appears under Phone numbers with Provisioned by set to Direct SIP.

Register your number with xAI using create a phone number. Set origin to byo_trunk, agent_id to your agent ID, and sip_auth.allowed_addresses to Plivo’s IP address ranges:

curl "https://api.x.ai/v2/phone-numbers" \
-H "Authorization: Bearer $XAI_API_KEY" \
-H 'Content-Type: application/json' \
-d '{
  "origin": "byo_trunk",
  "name": "Plivo inbound",
  "phone_number": "+15105550100",
  "agent_id": "<agent_id>",
  "sip_auth": {
    "allowed_addresses": [
      "13.52.9.0/25", "216.120.187.128/26",
      "18.214.109.128/25", "18.215.142.0/26", "204.89.148.128/26",
      "3.120.121.128/26",
      "18.228.70.64/26", "54.233.191.0/27",
      "13.238.202.192/26",
      "18.136.1.128/26", "204.89.149.128/27",
      "15.207.90.192/31", "204.89.151.128/27", "204.89.151.160/27"
    ]
  }
}'

import os
import requests

plivo_ip_ranges = [
    "13.52.9.0/25", "216.120.187.128/26",
    "18.214.109.128/25", "18.215.142.0/26", "204.89.148.128/26",
    "3.120.121.128/26",
    "18.228.70.64/26", "54.233.191.0/27",
    "13.238.202.192/26",
    "18.136.1.128/26", "204.89.149.128/27",
    "15.207.90.192/31", "204.89.151.128/27", "204.89.151.160/27",
]

response = requests.post(
    "https://api.x.ai/v2/phone-numbers",
    headers={"Authorization": f"Bearer {os.environ['XAI_API_KEY']}"},
    json={
        "origin": "byo_trunk",
        "name": "Plivo inbound",
        "phone_number": "+15105550100",
        "agent_id": "<agent_id>",
        "sip_auth": {"allowed_addresses": plivo_ip_ranges},
    },
)
print(response.json())

const plivoIpRanges = [
  '13.52.9.0/25', '216.120.187.128/26',
  '18.214.109.128/25', '18.215.142.0/26', '204.89.148.128/26',
  '3.120.121.128/26',
  '18.228.70.64/26', '54.233.191.0/27',
  '13.238.202.192/26',
  '18.136.1.128/26', '204.89.149.128/27',
  '15.207.90.192/31', '204.89.151.128/27', '204.89.151.160/27',
];

const response = await fetch('https://api.x.ai/v2/phone-numbers', {
  method: 'POST',
  headers: {
    'Authorization': `Bearer ${process.env.XAI_API_KEY}`,
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    origin: 'byo_trunk',
    name: 'Plivo inbound',
    phone_number: '+15105550100',
    agent_id: '<agent_id>',
    sip_auth: { allowed_addresses: plivoIpRanges },
  }),
});
console.log(await response.json());

A successful response returns HTTP 201 with the registered number. Copy the phone_number_id if you plan to update the number later:

{
  "phone_number": {
    "phone_number_id": "<phone_number_id>",
    "team_id": "<team_id>",
    "phone_number": "+15105550100",
    "name": "Plivo inbound",
    "agent_id": "<agent_id>",
    "origin": "byo_trunk",
    "sip_host": "<sip_host>",
    "inbound_trunk_id": "<inbound_trunk_id>",
    "sip_auth": {
      "allowed_addresses": [
        "13.52.9.0/25",
        "216.120.187.128/26",
        "18.214.109.128/25",
        "18.215.142.0/26",
        "204.89.148.128/26",
        "3.120.121.128/26",
        "18.228.70.64/26",
        "54.233.191.0/27",
        "13.238.202.192/26",
        "18.136.1.128/26",
        "204.89.149.128/27",
        "15.207.90.192/31",
        "204.89.151.128/27",
        "204.89.151.160/27"
      ]
    },
    "created_at": "2026-09-25T22:33:26.376958+00:00",
    "updated_at": "2026-09-25T22:33:26.376958+00:00"
  }
}

Test the integration

Call your Plivo phone number. The agent answers with its welcome message.
In the xAI Console, open your agent and select the Conversations tab. Select a call to see its transcript, per-turn audio, and raw events. xAI keeps conversations for 30 days.

Outbound calls

xAI Voice Agents don’t support outbound calling. You don’t need a Plivo outbound trunk for this integration.

Use SIP digest authentication

To authenticate Plivo with a SIP username and password instead of IP address ranges, add the same credentials in Plivo and xAI:

Username: 5 to 20 characters, alphanumeric only.
Password: 5 to 20 characters, using only alphanumeric characters and the special characters ~!@#$%^&*()_+, with at least one special character.

In Plivo, turn on authentication for the trunk’s primary URI:

Console
API

Navigate to SIP Trunking → Inbound Trunks and open your xAI trunk.
Open the Primary URI list and select the pencil icon next to the xAI URI.
Turn on Authentication needed, then enter the Username and Password.
Select Update URI.

Update the origination URI with authentication_needed, username, and password:

printf '%s' '<password>' | plivo sip uris update <uri_uuid> --authentication-needed=true --username <username> --password-stdin

curl "https://api.plivo.com/v1/Account/$PLIVO_AUTH_ID/Zentrunk/URI/<uri_uuid>/" \
-u "$PLIVO_AUTH_ID:$PLIVO_AUTH_TOKEN" \
-H 'Content-Type: application/json' \
-d '{
  "authentication_needed": true,
  "username": "<username>",
  "password": "<password>"
}'

import os
import requests

auth_id = os.environ["PLIVO_AUTH_ID"]
auth_token = os.environ["PLIVO_AUTH_TOKEN"]

response = requests.post(
    f"https://api.plivo.com/v1/Account/{auth_id}/Zentrunk/URI/<uri_uuid>/",
    auth=(auth_id, auth_token),
    json={
        "authentication_needed": True,
        "username": "<username>",
        "password": "<password>",
    },
)
print(response.json())

const authId = process.env.PLIVO_AUTH_ID;
const authToken = process.env.PLIVO_AUTH_TOKEN;
const authHeader = 'Basic ' + Buffer.from(`${authId}:${authToken}`).toString('base64');

const response = await fetch(`https://api.plivo.com/v1/Account/${authId}/Zentrunk/URI/<uri_uuid>/`, {
  method: 'POST',
  headers: {
    'Authorization': authHeader,
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    authentication_needed: true,
    username: '<username>',
    password: '<password>',
  }),
});
console.log(await response.json());

In xAI, add the same credentials to your phone number:

Console
API

When you add the number in Assign the number to your agent, expand Authentication and enter the Username and Password. You can leave Allowed addresses empty.You can’t change the authentication of a number you already added. To switch an existing number to SIP digest authentication, select ⋯ → Edit → Remove number on the number under Phone numbers, and then add it again.

curl "https://api.x.ai/v2/phone-numbers" \
-H "Authorization: Bearer $XAI_API_KEY" \
-H 'Content-Type: application/json' \
-d '{
  "origin": "byo_trunk",
  "name": "Plivo inbound",
  "phone_number": "+15105550100",
  "agent_id": "<agent_id>",
  "sip_auth": {
    "auth_username": "<username>",
    "auth_password": "<password>"
  }
}'

import os
import requests

response = requests.post(
    "https://api.x.ai/v2/phone-numbers",
    headers={"Authorization": f"Bearer {os.environ['XAI_API_KEY']}"},
    json={
        "origin": "byo_trunk",
        "name": "Plivo inbound",
        "phone_number": "+15105550100",
        "agent_id": "<agent_id>",
        "sip_auth": {
            "auth_username": "<username>",
            "auth_password": "<password>",
        },
    },
)
print(response.json())

const response = await fetch('https://api.x.ai/v2/phone-numbers', {
  method: 'POST',
  headers: {
    'Authorization': `Bearer ${process.env.XAI_API_KEY}`,
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    origin: 'byo_trunk',
    name: 'Plivo inbound',
    phone_number: '+15105550100',
    agent_id: '<agent_id>',
    sip_auth: {
      auth_username: '<username>',
      auth_password: '<password>',
    },
  }),
});
console.log(await response.json());

A successful response returns HTTP 201. The sip_auth object contains only the username:

{
  "phone_number": {
    "phone_number_id": "<phone_number_id>",
    "team_id": "<team_id>",
    "phone_number": "+15105550100",
    "name": "Plivo inbound",
    "agent_id": "<agent_id>",
    "origin": "byo_trunk",
    "sip_host": "<sip_host>",
    "inbound_trunk_id": "<inbound_trunk_id>",
    "sip_auth": {
      "auth_username": "<username>"
    },
    "created_at": "2026-09-25T22:33:26.376958+00:00",
    "updated_at": "2026-09-25T22:33:26.376958+00:00"
  }
}

xAI never returns the password, and you can’t change the authentication of an existing number. To change it, delete the number and register it again.

Make changes after setup

Update the agent

To change the agent’s instructions, voice, or tools, edit the agent in the xAI Console and select Publish. Nothing changes in Plivo.

Update a registered number

You can rename a registered number, and with the API, route it to a different agent. Its allowed IP address ranges and SIP credentials can’t be changed in place: remove the number and add it again with the new values.

Console
API

Open the agent’s Deployment tab and select ⋯ → Edit on the number.
Change the Name and select Save.
To change the allowed IP address ranges or SIP credentials, select Remove number, and then add the number again.

Send these requests to https://api.x.ai. For PATCH, put the fields to change in phone_number and list them in field_mask.paths. Only name and agent_id can be changed this way:

Task	Request
List your numbers and their `phone_number_id`	`GET /v2/phone-numbers`
Route the number to a different agent	`PATCH /v2/phone-numbers/<phone_number_id>` with `{"phone_number": {"agent_id": "<agent_id>"}, "field_mask": {"paths": ["agent_id"]}}`
Rename the number	`PATCH /v2/phone-numbers/<phone_number_id>` with `{"phone_number": {"name": "<name>"}, "field_mask": {"paths": ["name"]}}`
Change the allowed IP address ranges or SIP credentials	`DELETE /v2/phone-numbers/<phone_number_id>`, and then register the number again as in Assign the number to your agent

Troubleshooting

SIP configuration errors typically surface only when a call is placed. If a call fails, check the following common issues:

Issue	Solution
Call fails and doesn’t appear in the agent’s Conversations	Verify the trunk’s primary URI is `sip.voice.x.ai;transport=tls`, and that your phone number’s Application Type is SIP Trunk with your xAI trunk selected. In xAI, verify the number is in E.164 format with a leading `+`.
Call is rejected by xAI	Verify Allowed addresses includes all of Plivo’s IP address ranges. If you use SIP digest authentication, verify the username and password match exactly in Plivo and xAI.
Agent uses old instructions	Select Publish in the xAI Console. Calls use the published version, not the draft.
Agent stays silent when the call connects	Welcome message is off, so the agent waits for the caller to speak first. Turn it on to have the agent greet callers.

Debug logs:

Call doesn’t reach the agent: first check the Plivo logs, then the agent’s Conversations tab in the xAI Console.
Call reaches the agent but behaves unexpectedly: check the call’s transcript and Raw events in the agent’s Conversations tab.

For error codes, see Plivo hangup codes.

SIP Trunking API overview

Plivo SIP Trunking API reference.

SIP Trunking overview

Plivo SIP trunking documentation.

xAI SIP Phone Calls

xAI’s SIP documentation.

xAI Voice API reference

xAI phone number and realtime API reference.

Getting Started

Integration Guides

Deploy

Reference

xAI Voice Agents Integration

How the integration works

Prerequisites

Inbound calls

Create a voice agent in the xAI Console

Configure and publish the agent

Create an inbound trunk in Plivo

Connect your phone number

Assign the number to your agent

Test the integration

Outbound calls

Use SIP digest authentication

Make changes after setup

Update the agent

Update a registered number

Troubleshooting

SIP Trunking API overview

SIP Trunking overview

xAI SIP Phone Calls

xAI Voice API reference

​How the integration works

​Prerequisites

​Inbound calls

Create a voice agent in the xAI Console

Configure and publish the agent

Create an inbound trunk in Plivo

Connect your phone number

Assign the number to your agent

Test the integration

​Outbound calls

​Use SIP digest authentication

​Make changes after setup

​Update the agent

​Update a registered number

​Troubleshooting

​Related

SIP Trunking API overview

SIP Trunking overview

xAI SIP Phone Calls

xAI Voice API reference

How the integration works

Prerequisites

Inbound calls

Outbound calls

Use SIP digest authentication

Make changes after setup

Update the agent

Update a registered number

Troubleshooting

Related