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Overview

Vonage (formerly Nexmo) is a cloud communications platform with global voice capabilities. Voicerix uses Vonage’s application-level voice API with high-quality 16kHz audio for clear, natural conversations.

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Prerequisites

  • A Vonage account
  • A Vonage Application with Voice capability enabled
  • Application ID and Private Key from your Vonage Dashboard
  • API Key and API Secret from your Vonage Dashboard
  • At least one Vonage phone number linked to the application

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Configuration

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Step 1: Create a Vonage Application

  1. Log in to your Vonage Dashboard
  2. Navigate to Applications → Create a new application
  3. Enable the Voice capability
  4. Generate a private key (save this securely — you’ll need it)
  5. Note your Application ID

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Step 2: Get API Credentials

  1. Find your API Key and API Secret under API Settings in the dashboard
  2. Navigate to Numbers → Your Numbers and link your phone numbers to the application

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Step 3: Add Configuration in Voicerix

  1. In Voicerix, go to Integrations and click Add configuration
  2. Select Vonage as your provider
  3. Enter your credentials:
    • Application ID
    • Private Key (include the full key with BEGIN/END lines)
    • API Key
    • API Secret
  4. Click Save Configuration
  5. Open the saved configuration and add at least one phone number without the + prefix (e.g. 14155551234)

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Step 4: Test

  1. Go to Agents, open a workflow, and click Test Call
  2. Check the call logs to confirm a successful connection

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Inbound Calling Setup

Vonage configures inbound webhooks at the application level — a single Answer URL on the Vonage application applies to every number linked to it. When you save an inbound workflow on a phone number in Voicerix, Voicerix automatically pushes the webhook URL to your Vonage Application’s Answer URL.
  1. Open the Vonage Dashboard
  2. Under Numbers → Your Numbers, link each number you want for inbound to the same Vonage Application whose ID you configured in Voicerix

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Step 2: Assign an Inbound Workflow in Voicerix

  1. In Voicerix, go to Integrations and open your Vonage configuration
  2. In the Phone numbers section, edit the number that should receive inbound calls
  3. Set its Inbound workflow to the agent that should answer
  4. Save

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Step 3: Verify in Vonage Dashboard

  1. Open your Vonage Application in the Vonage Dashboard
  2. Under Capabilities → Voice, confirm:
    • Answer URL is set to: https://client.voicerix.ai/api/v1/telephony/inbound/run
    • HTTP Method is POST
Voicerix pushes this URL automatically when you save the inbound workflow. If the field is empty or shows a different URL, the auto-push failed — usually because the API Key/Secret or Application ID is incorrect. Paste the URL manually, set the method to POST, and save the application.

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Step 4: Test Inbound

  1. Call your Vonage number from another phone
  2. Verify your voice agent answers and responds
  3. Check call logs in both Voicerix and the Vonage Dashboard

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Audio Quality

Vonage uses 16kHz audio, which gives:
  • Clearer voice reproduction
  • Better speech recognition accuracy
  • More natural TTS output
  • Fewer transcription errors

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Troubleshooting

  • Ensure Voice is enabled in your Vonage application
  • Verify the Application ID matches your configuration
  • Check that your phone numbers are linked to the application
  • Verify your private key is complete (including BEGIN/END lines)
  • Check the Application ID is correct
  • Ensure the private key hasn’t been regenerated in Vonage Dashboard
Remove the + prefix for Vonage numbers (use 14155551234, not +14155551234)
  • Verify the WebSocket connection is established
  • Check the audio pipeline is configured for 16kHz PCM
  • Monitor WebSocket for binary audio frames
  • Check WebSocket heartbeat/ping-pong frames
  • Verify no timeout in load balancer or proxy
  • Monitor for audio pipeline errors
  • Verify the Vonage application’s Answer URL is set to https://client.voicerix.ai/api/v1/telephony/inbound/run
  • Ensure the Answer URL is publicly accessible
  • Confirm the called number is linked to the correct Vonage application
  • Confirm the called number has an Inbound workflow assigned in Voicerix
  • Confirm the phone number has an Inbound workflow assigned in Integrations
  • Verify the API Key matches the one stored in your Voicerix configuration
  • Verify WebSocket connection establishes successfully
  • Review call logs for error messages

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Best Practices

  • Keep your private key secure — it is stored encrypted in Voicerix
  • Test your configuration with a single call before running campaigns
  • Monitor the Vonage Dashboard for usage and billing