VEXYL Voice Gateway

Connect any phone line
to AI, in real time

The VEXYL Voice Gateway bridges SIP trunks, PSTN, Asterisk, FreePBX, business PBXs and WebRTC to the speech recognition, AI and voices you choose. Self-host it next to your PBX, or use it on VEXYL Cloud.

; Asterisk dialplan: hand the call to AI
[voice-assistant]
exten => _X.,1,Answer()
 same => n,Set(SESSION_UUID=${TRIM(${SHELL(uuidgen)})})
 same => n,AudioSocket(${SESSION_UUID},127.0.0.1:8080)
 same => n,Hangup()

# or place an outbound AI call
POST /outbound/initiate
{ "phoneNumber": "+919876543210" }

Built for real telephony

Asterisk & FreePBX

AudioSocket over TCP straight from your dialplan, or a SIP trunk. Barge-in, DTMF and call transfers.

SIP trunks & PSTN

Accept calls from carrier trunks and PBXs, with or without registration. G.711 and Opus.

Business PBXs

Panasonic KX-NS / KX-NSX, Avaya IP Office, Grandstream UCM and Bitvoice, as a trunk or an extension.

Browser widget

WebRTC voice on your website over a WebSocket, with the same agent as your phone line.

Outbound calls

Start calls by API with per-call context and settings; follow them with lifecycle webhooks.

Realtime mode

Pipe audio to a realtime speech-to-speech model for the most natural turn-taking.

Conversation behaviour

Voice-activity detection, interruption handling, noise floor and silence settings you can tune.

Webhooks & billing

Signed lifecycle events and per-call usage so you can bill and report accurately.

Security & operations

IP allow-lists, health probes, logs and production runbooks in the docs.

The voice stack architecture

A modular pipeline that decouples telephony from intelligence. Swap any component without rewriting code.

1

Input layer

Takes raw audio from Asterisk (AudioSocket over TCP), SIP trunks and PBXs, or web browsers (WebSocket).

2

Intelligence layer

Streams audio to speech recognition, sends text to the AI brain (LiteBot or your HTTP endpoint), and manages conversation state.

3

Output layer

Synthesises the reply, caches repeated phrases, and streams audio back to the caller with smart buffering.

Caller
SIP / PBX / WebRTC
VEXYL Gateway
STT
AI brain
LiteBot / HTTP
TTS

Your choice of providers

Bring your own keys and pay providers directly. Switch per deployment or per call.

Speech to text

Sarvam Google Deepgram Groq Gemini VEXYL-STT

AI brain

LiteBot n8n Flowise Custom HTTP

Text to speech

Sarvam ElevenLabs Google Gemini Azure Deepgram Smallest
Outbound

Don't wait for calls. Start them.

Reminders, collections and surveys triggered by API, with context injected into the agent and no awkward silence when the customer says hello.

Deploy in minutes

Install script

Standalone binary, set up for you.

curl -fsSL https://vexyl.ai/downloads/install_gateway.sh | sudo bash

Docker

Runs anywhere Docker runs.

docker pull vexyl/vexyl-voice-gateway:latest

Binary

For bare-metal and air-gapped servers.

Download vexyl-gateway.zip

Kubernetes

High availability with auto-scaling.

kubectl apply -f vexyl-deployment.yaml

Full steps in the binary and Docker quick starts. Part of VEXYL Studio.

Self-host the gateway or use VEXYL Cloud

Same platform, two ways to run it. Start self-hosted for free, or let us run it for you on VEXYL Cloud.

Self-hosted

Run the gateway and LiteBot on your own servers or VPC. Your audio, transcripts and keys never leave your infrastructure.

  • Free Developer edition, 4 concurrent calls
  • Single binary or Docker
  • Bring your own SIP trunk and model keys
Self-host free

VEXYL Cloud

We run the gateway for you. Point a SIP trunk from your PBX at us, drop the browser widget on your site, and receive signed webhooks.

  • No servers or config files to manage
  • DID-to-bot mapping done for you
  • Opus, mu-law and A-law trunks
Talk to sales

Frequently Asked Questions

What is the VEXYL Voice Gateway?

The VEXYL Voice Gateway connects phone calls and browser audio to AI. It takes audio from a SIP trunk, Asterisk, an IP PBX or a web page, sends it to a speech recognition provider, passes the text to the AI brain, and speaks the reply back with a text-to-speech voice, in real time.

How does the gateway connect to Asterisk and FreePBX?

Through AudioSocket over TCP, straight from your dialplan, or through a SIP trunk. Barge-in, DTMF and call transfers are supported.

Which PBXs and carriers are supported?

Any SIP trunk that speaks G.711, Asterisk and FreePBX, and IP PBXs including Panasonic KX-NS / KX-NSX, Avaya IP Office, Grandstream UCM and Bitvoice, either as a trunk or as a PBX extension.

Can the gateway make outbound calls?

Yes. Start a call with POST /outbound/initiate and pass JSON context that is injected into the agent prompt. Webhooks report initiated, answered, completed and failed events. For CSV campaigns, use the LiteBot auto-dialer.

What AI brain does the gateway use?

Either LiteBot, which gives you managed bots with prompts, tools, transfers and end-of-call hooks, or your own HTTP endpoint, such as an n8n or Flowise workflow or a custom backend.

How do I install it?

Use the install script, Docker, or the standalone binary for bare-metal and air-gapped servers. Or skip installation and use the gateway on VEXYL Cloud.