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Overview

Telnyx provides programmable voice via its Call Control API. Voicerix uses Call Control plus WebSocket media streaming to power your voice agents.

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Prerequisites

  • A Telnyx account
  • An API Key from the Telnyx Mission Control Portal
  • A Call Control Application — or leave blank and Voicerix will auto-create one for you
  • At least one Telnyx phone number assigned to that Call Control Application

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Configuration

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Step 1: Get Telnyx Credentials

  1. Log in to the Telnyx Mission Control Portal
  2. Navigate to API Keys and create or copy an API Key
  3. (Optional) Navigate to Call Control → Applications, open the application you’ll use with Voicerix, and copy its Connection ID (Call Control App ID). Skip this if you want Voicerix to auto-create the application.
  4. Navigate to Numbers → My Numbers and assign your phone numbers to the Call Control Application

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Step 2: Add Configuration in Voicerix

  1. In Voicerix, go to Integrations and click Add configuration
  2. Select Telnyx as your provider
  3. Enter your credentials:
    • API Key
    • Call Control App ID (optional — leave blank to auto-create)
  4. Click Save Configuration
  5. Open the saved configuration and add at least one phone number in E.164 format (e.g. +1234567890)
If Voicerix auto-created the Call Control Application, you still need to assign your Telnyx numbers to that application in the Telnyx Portal under Numbers → My Numbers. The auto-created application is named voicerix-<random> — its Connection ID is shown on the saved configuration.

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Step 3: 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

Telnyx delivers inbound webhooks at the Call Control Application level — the webhook URL is configured once on the application and applies to every number assigned to it. When you save an inbound workflow on a phone number in Voicerix, Voicerix automatically pushes the webhook URL to your Call Control Application’s webhook_event_url. If Voicerix auto-created the application, the webhook URL is already set.

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Step 1: Assign an Inbound Workflow

  1. In Voicerix, go to Integrations and open your Telnyx 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 2: Verify in Telnyx Portal

  1. Go to Call Control → Applications in the Telnyx Portal
  2. Open the application whose Connection ID you configured in Voicerix
  3. Under Webhook Settings, confirm:
    • Webhook URL is set to: https://client.voicerix.ai/api/v1/telephony/inbound/run
    • HTTP Method is POST
  4. Make sure the phone numbers you want for inbound are assigned to this application
Voicerix pushes this URL automatically when you save the inbound workflow. The same URL is shared across every number on the Call Control Application — Voicerix matches the inbound call to the right agent using the called number’s inbound workflow assignment. If the field is empty or shows a different URL, the auto-push failed — usually because the API Key or Connection ID is incorrect. Paste the URL manually, set the method to POST, and save.

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Step 3: Test Inbound

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

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Troubleshooting

Ensure phone numbers include the country code in E.164 format: +1234567890
  • Verify the API Key is correct and active
  • Check for extra spaces in the key
  • Ensure the key hasn’t been revoked in the Telnyx Portal
  • Telnyx signs webhooks with Ed25519 — confirm the public key on the application hasn’t changed
  • Verify the webhook URL matches what Telnyx sends
  • Check if you’re behind a proxy that modifies request bodies
  • Verify the WebSocket connection is established
  • Check firewall rules for WebSocket traffic
  • Ensure the audio pipeline is configured correctly
  • Verify the Call Control Application’s webhook URL is set to https://client.voicerix.ai/api/v1/telephony/inbound/run
  • Ensure the webhook URL is publicly accessible
  • Confirm the called number is assigned to the same Call Control Application whose Connection ID is in Voicerix
  • 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

  • Test your configuration with a single call before running campaigns
  • Monitor the Telnyx Portal for usage and billing
  • Use a dedicated Call Control Application for Voicerix so the shared webhook URL doesn’t conflict with other systems