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This guide shows the pattern for answering inbound phone calls with your AI voice agent over Vobiz. Vobiz provides the phone number and the SIP rails that carry the call; your agent platform (Vapi, Retell, ElevenLabs, LiveKit, OpenAI Realtime, or a self-hosted pipeline) runs the conversation.
The exact UI steps differ per platform. This guide explains the shared inbound pattern and the values you map between the two systems. For click-by-click steps and screenshots, follow your platform’s integration page under Integrations.

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How inbound works

Caller dials your Vobiz number → Vobiz inbound trunk → your AI platform's SIP endpoint → your AI agent answers
Vobiz receives the call on your number and forwards it to your agent platform. There are two transport styles, depending on the platform:
  • SIP (Vapi, Retell, ElevenLabs, LiveKit, OpenAI Realtime, 3CX) - Vobiz routes the call leg to the platform’s SIP URI. No server of your own is required.
  • WebSocket <Stream> (Pipecat, Dograh, custom) - Vobiz POSTs your answer_url, you return a <Stream> XML response, and audio flows over a WebSocket to your own server.

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Prerequisites

  • A Vobiz account with a phone number.
  • An account on your chosen AI voice platform, with an agent/assistant already created.
  • Access to the SIP Trunk section of the Vobiz Console.

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Pattern A: SIP platforms

This is the path for most managed platforms.
1

Get the platform's inbound SIP URI

In your AI platform, create an inbound SIP trunk and copy its SIP URI, for example:
  • Vapi: <trunk_id>.sip.vapi.ai (the Trunk ID is read via the Vapi API, not the dashboard)
  • LiveKit: <your-sip-uri>.sip.livekit.cloud
Strip any sip: prefix - you enter the hostname only.
2

Whitelist the Vobiz gateway IP on the platform

Configure the platform’s inbound trunk to accept calls from the Vobiz gateway:
SettingValue
Gateway IP13.233.44.61
Port5060
Netmask32
ProtocolUDP
InboundEnabled
On platforms that use an allow-list (for example, LiveKit’s Allowed Addresses), you can use 0.0.0.0/0 while testing and tighten it to the Vobiz gateway in production.
3

Create a Vobiz inbound trunk

In the Vobiz Console, go to SIP Trunk → Inbound Trunk and create a trunk:
  • Transport: UDP
  • Primary URI: the platform SIP URI from Step 1 (hostname only, no sip:)
  • Link your Vobiz phone number to this trunk and save.
4

Assign your agent and test

On the platform side, attach your AI agent/assistant to the inbound number, then dial your Vobiz number from any phone. Your agent should answer.
Calls to your Vobiz number now route to your AI agent automatically.

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Pattern B: self-hosted WebSocket platforms

For Pipecat, Dograh, or a custom pipeline you run yourself, Vobiz reaches your server over HTTP/WebSocket instead of SIP.
1

Create a Vobiz application

In the Vobiz Console, open Applications → Create New Application. Set the Answer URL to your server’s /answer route and the method to POST.
2

Assign your number to the application

Go to Phone Numbers, select your number, and assign it to the application.
3

Return a Stream response

When a call comes in, Vobiz POSTs your answer_url. Return a <Stream> response pointing at your WebSocket:
<Response>
  <Stream url="wss://your-server/ws" />
</Response>
Vobiz opens the WebSocket and exchanges JSON frames (start, media every 20 ms, playAudio, clearAudio, stop). Audio is G.711 μ-law, 8 kHz, 160-byte (20 ms) chunks. See the Stream XML reference and the WebSockets integration.

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Credential and URI mapping

Direction of trustValueWhere it lives
Vobiz → platform (where to send the call)Platform SIP URI, e.g. <id>.sip.vapi.aiVobiz inbound trunk Primary URI
Platform trusts VobizGateway IP 13.233.44.61 (UDP/5060)Platform inbound trunk allow-list

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Troubleshooting

  • Call disconnects immediately: confirm the platform’s SIP URI is entered without the sip: prefix, and that your Vobiz number is linked to the inbound trunk.
  • Caller hears nothing / agent never answers: verify the gateway IP 13.233.44.61 is whitelisted on the platform, and that your agent is published and attached to the number.
  • Wrong domain: use the platform’s exact SIP URI - a generic host won’t authenticate.

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Next steps