Vonage

Vonage sends a webhook when a call arrives. Rapida responds with an NCCO (Nexmo Call Control Object) that opens a WebSocket carrying Linear PCM 16kHz audio — higher quality than Twilio’s μ-law.

Vault Credentials

In the Rapida dashboard go to Credentials → Create Credential, select provider type Vonage:

Key	Description
`api_key`	Vonage API key
`api_secret`	Vonage API secret
`application_id`	Vonage Application ID (required for JWT auth on outbound)
`private_key`	Vonage Application private key — PEM string (required for JWT auth on outbound)

Setup

Set PUBLIC_ASSISTANT_HOST

PUBLIC_ASSISTANT_HOST is the public HTTPS hostname Vonage will use to reach your server — for the answer URL and the WebSocket media stream.

Production
Local Development (ngrok)

Set it in docker/assistant-api/.assistant.env:

PUBLIC_ASSISTANT_HOST=your-server.com   # no https:// prefix

Also update connection.media in ui/src/configs/config.production.json:

{
  "connection": {
    "media": "https://your-server.com"
  }
}

Vonage’s servers cannot reach localhost. Use ngrok to create a public HTTPS tunnel:1. Install and authenticate ngrok

# macOS
brew install ngrok/ngrok/ngrok

# Linux
curl -sSL https://ngrok-agent.s3.amazonaws.com/ngrok.asc \
  | sudo tee /etc/apt/trusted.gpg.d/ngrok.asc >/dev/null
echo "deb https://ngrok-agent.s3.amazonaws.com buster main" \
  | sudo tee /etc/apt/sources.list.d/ngrok.list
sudo apt update && sudo apt install ngrok

ngrok config add-authtoken <your-authtoken>

Get your authtoken at dashboard.ngrok.com.2. Start the tunnel (keep this running)

ngrok http 8080
# Forwarding  https://abc123.ngrok-free.app -> http://localhost:8080

3. Update two files with the ngrok hostname

File	Field	Value
`docker/assistant-api/.assistant.env`	`PUBLIC_ASSISTANT_HOST`	`abc123.ngrok-free.app` (no `https://`)
`ui/src/configs/config.development.json`	`connection.media`	`https://abc123.ngrok-free.app` (with `https://`)

# docker/assistant-api/.assistant.env
PUBLIC_ASSISTANT_HOST=abc123.ngrok-free.app

// ui/src/configs/config.development.json
{
  "connection": {
    "media": "https://abc123.ngrok-free.app"
  }
}

4. Rebuild

make rebuild-assistant

The free ngrok tier generates a new URL on every restart. Use a free static domain (ngrok http --domain=your-name.ngrok-free.app 8080) so you only need to update Vonage’s answer URL once.

Create a Vonage Voice Application

In Vonage Dashboard → Applications → Create a new application, enable Voice capability and set:

Field	Value
Answer URL (POST)	`https://{PUBLIC_ASSISTANT_HOST}/v1/talk/vonage/call/{assistantId}?x-api-key={apiKey}`
Event URL (POST)	`https://{PUBLIC_ASSISTANT_HOST}/v1/talk/vonage/ctx/{contextId}/event?x-api-key={apiKey}`

Click Generate public and private key — download the private key and store the PEM content in the vault credential’s private_key field.

Link a Vonage number

In Numbers, assign a virtual number to the application you just created.

Attach vault credential to the assistant

In the assistant’s Phone Deployment, select the Vonage vault credential.

Verify

curl https://{PUBLIC_ASSISTANT_HOST}/readiness/
# Expected: {"status":"ok"}

What Rapida Returns

When Vonage hits the answer URL, Rapida responds with an NCCO:

[{
  "action": "connect",
  "endpoint": [{
    "type": "websocket",
    "uri": "wss://{PUBLIC_ASSISTANT_HOST}/v1/talk/vonage/ctx/{contextId}?x-api-key={apiKey}",
    "content-type": "audio/l16;rate=16000"
  }]
}]

Audio Spec

Property	Value
Encoding	Linear PCM 16-bit
Sample rate	16000 Hz
Channels	Mono
Transport	Raw binary WebSocket frames

16kHz Linear PCM improves STT accuracy over 8kHz μ-law (Twilio/Exotel), particularly for providers that natively support 16kHz input.

Twilio

Alternative global PSTN provider

Exotel

India / SEA PSTN

Telephony Overview

All providers and URL routing reference

Configuration

Full env var reference

Getting Started

Dashboard (UI)

Web API

Assistant API

Integration API

Endpoint API

Document API

Vault Credentials

Setup

What Rapida Returns

Audio Spec

Twilio

Exotel

Telephony Overview

Configuration

​Vault Credentials

​Setup

​What Rapida Returns

​Audio Spec

Twilio

Exotel

Telephony Overview

Configuration

Vault Credentials

Setup

What Rapida Returns

Audio Spec