> ## Documentation Index
> Fetch the complete documentation index at: https://docs.poly.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Numbers

> Connect phone numbers to your agent using PolyAI, Twilio, or outbound calling

Numbers is how PolyAI connects your agent to the public phone network. Provision a number directly through PolyAI, bring your own Twilio number, or route through your existing contact-centre provider — every option terminates on the same agent runtime so the conversation logic is identical across channels. Manage everything in the **Numbers** tab on the Voice page, where you configure SIP addresses (Main SIP and Fallback SIP) and view the numbers assigned to each environment.

<img src="https://mintcdn.com/polyai/mC-hBNxhbQLRsMMg/images/voice/numbers-tab.png?fit=max&auto=format&n=mC-hBNxhbQLRsMMg&q=85&s=5f7a6eb64a2a5cbebab7c5efb1240bc9" alt="Voice Numbers tab" width="3006" height="1476" data-path="images/voice/numbers-tab.png" />

| Option                                          | Best for              | What you get                                               |
| ----------------------------------------------- | --------------------- | ---------------------------------------------------------- |
| **[Buy a number](./how-to-buy-number)**         | No existing provider  | Purchase directly from PolyAI.                             |
| **[Twilio integration](./twilio/introduction)** | Existing Twilio setup | Connect your Twilio numbers. Voice, SMS, and Flex routing. |
| **[Outbound calling](./outbound-calling)**      | Proactive outreach    | Agent-initiated calls through API or SIP.                  |

<Note>
  You can also connect through other contact center platforms like [Genesys](/integrations/voice/sip/genesys), [Five9](/integrations/voice/sip/five9), or [NICE CXone](/integrations/voice/sip/NICECXone) with SIP. See [Integrations](/integrations/introduction) for the full list.
</Note>

## Integration options

<CardGroup cols={2}>
  <Card title="Buy a number" icon="cart-shopping" href="./how-to-buy-number">
    Purchase a number directly from PolyAI.
  </Card>

  <Card title="Twilio integration" icon="phone" href="./twilio/introduction">
    Voice, SMS, and contact center routing with Twilio.
  </Card>

  <Card title="Outbound calling" icon="phone-arrow-up-right" href="./outbound-calling">
    Agent-initiated calls for reminders and follow-ups.
  </Card>
</CardGroup>

## Twilio integration guides

* **[Twilio overview](./twilio/introduction)** – Benefits and setup overview
* **[Phone number integration](./twilio/how-to-integrate-voice)** – Connect a Twilio-hosted number
* **[SMS integration](/voice-channel/message-templates)** – Set up SMS messaging with Twilio
* **[Twilio Flex integration](/integrations/voice/twilio)** – Advanced contact center routing

## Outbound calling

Agent-initiated calls for reminders, follow-ups, and notifications.

* **[Outbound calling overview](./outbound-calling)** – Methods and best practices

* **[Outbound Calling API](/api-reference/outbound/introduction)** – Programmatically trigger calls

* **[SIP integration](/integrations/voice/sip/custom-sip)** – Route through your SIP infrastructure

## Automate with the Agents API

Telephony plumbing is scriptable too — helpful for bulk provisioning and for reshaping routing as part of a broader deployment.

<AccordionGroup>
  <Accordion title="Provision numbers and connectors via the Agents API" icon="code">
    Connectors bind phone numbers to voice infrastructure; phone numbers are E.164 strings routed through a connector. The [Agents API](/api-reference/agents/introduction) has CRUD for both.

    <CodeGroup>
      ```bash curl theme={"theme":{"light":"github-light","dark":"github-dark"}}
      # Import a phone number onto an existing connector
      curl -X POST https://api.us.poly.ai/v1/agents/AGENT_ID/telephony/phone-numbers/+442071234567 \
        -H "x-api-key: $POLYAI_API_KEY" \
        -H "Content-Type: application/json" \
        -d '{ "connectorId": "conn_abc123" }'

      # Reassign a number to a different connector
      curl -X PATCH https://api.us.poly.ai/v1/agents/AGENT_ID/telephony/phone-numbers/+442071234567 \
        -H "x-api-key: $POLYAI_API_KEY" \
        -H "Content-Type: application/json" \
        -d '{ "connectorId": "conn_new456" }'
      ```

      ```python Python theme={"theme":{"light":"github-light","dark":"github-dark"}}
      import os, requests

      BASE = "https://api.us.poly.ai"
      HEADERS = {"x-api-key": os.environ["POLYAI_API_KEY"]}

      # Look up which connector serves a given number
      resp = requests.post(
          f"{BASE}/v1/agents/{AGENT_ID}/telephony/connectors/lookup",
          headers=HEADERS,
          json={"phoneNumber": "+442071234567"},
      )
      connector = resp.json()
      ```
    </CodeGroup>

    See [Connectors](/api-reference/agents/endpoint/connectors/list-all-connectors-for-a-project) and [Phone numbers](/api-reference/agents/endpoint/phone-numbers/list-all-phone-numbers-for-a-project) for the full endpoint list.
  </Accordion>
</AccordionGroup>

## Related pages

<CardGroup cols={2}>
  <Card title="Route management" icon="route" href="/voice-channel/numbers/route-management">
    Configure how calls are routed to your agent
  </Card>

  <Card title="Integrations" icon="plug" href="/integrations/introduction">
    Connect to Genesys, Five9, NICE, and other platforms
  </Card>

  <Card title="SMS" icon="message" href="/voice-channel/message-templates">
    Send text messages during voice conversations
  </Card>

  <Card title="Phone number endpoints" icon="square-terminal" href="/api-reference/agents/endpoint/phone-numbers/list-all-phone-numbers-for-a-project">
    Import and reassign numbers via the Agents API.
  </Card>
</CardGroup>