Telephony
Phone call integration with Twilio and VoxImplant in Voxagent
Voxagent integrates with telephony providers to enable AI agents to make and receive phone calls.
Supported Providers
| Provider | Inbound | Outbound | Notes |
|---|---|---|---|
| Twilio | Yes | Yes | Direct SIP trunk integration |
| VoxImplant | Yes | Yes | Via WebSocket Media Bridge (no direct SIP access) |
| Custom SIP | Yes | Yes | Connect your own PBX / SIP trunk over standard SIP |
Inbound Calls
When a call comes in to a connected phone number:
- Telephony provider sends a webhook to the platform
- Webhook is received via Kafka
- Backend identifies the agent linked to the phone number
- LiveKit room is created with SIP participant
- AI agent is dispatched to the room
- Conversation begins
Phone Number Management
- Import existing numbers from Twilio or VoxImplant
- Link a phone number to a specific agent
- Configure per-number settings
Outbound Calls
Outbound calls can be initiated:
- Individually via the API
- In bulk via Outbound Campaigns
The platform creates a LiveKit room, dispatches the agent, and initiates the outbound call via the configured telephony provider.
Custom SIP
In addition to the Twilio and VoxImplant integrations, Voxagent lets you connect any SIP telephony — your own PBX (Mango Office, Asterisk, FreeSWITCH, PBX-as-a-Service, etc.) — over standard SIP. The LiveKit server acts as the SIP endpoint on both sides:
- Inbound (PBX → LiveKit): your SIP provider sends
INVITEto the public LiveKit SIP domain. Authorization is enforced by an IP allowlist and optional Digest auth. - Outbound (LiveKit → PBX): LiveKit dials
INVITEto your PBX's SIP server. Authentication is an optional Digest username/password or IP-trust (the PBX trusts our outbound IPs).
For each account the admin configures the PBX SIP server, transport, destination country, allowed inbound IPs, and credential pairs. Once created, the platform returns the public SIP gateway domain and the list of our outbound IPs — admins share these with the PBX owner so the routing can be wired up.
A step-by-step setup for both sides is in the Custom SIP guide.
VoxImplant Integration
VoxImplant does not provide direct SIP trunk access. The platform uses a WebSocket Media Bridge — a Node.js service that:
- Receives audio from VoxImplant via WebSocket
- Streams it into a LiveKit room
- Sends LiveKit audio back to VoxImplant
This allows full agent functionality with VoxImplant as the telephony backend.
SIP Trunk (LiveKit)
LiveKit Server includes a built-in SIP component that handles:
- SIP trunk registration
- Dispatch rules for routing calls to rooms
- Direct SIP-to-WebRTC bridging (for providers that support it)