How to Connect WhatsApp Calling to AI Voice Agents

WhatsApp has over 3.3 billion monthly active users, on track to reach 3.5 billion by the end of 2026. In many of the world's largest markets, it is the primary way people communicate with businesses.

The scale is lopsided toward exactly the markets where voice matters most. India leads with over 535 million users, followed by Brazil at 148 million and Indonesia at 112 million. In Brazil, Indonesia, and Nigeria, WhatsApp penetration runs above 90% of smartphone users. Across LATAM, MENA, and APAC, it has quietly replaced SMS, email, and the phone dialer. For hundreds of millions of people, WhatsApp is the main communication channel.

Until recently, those conversations were limited to text. Now, with WhatsApp Business Calling, your customers can tap a button and talk to your business over a voice call, directly inside WhatsApp. And when you connect those calls to an AI voice agent, every inbound and outbound call is answered instantly, 24/7, in any language.

In this guide, we will walk through how to set up WhatsApp Business Calling with Telnyx AI voice agents, from enabling the feature to placing your first AI-powered call.

Why WhatsApp Calling + AI Agents?

The AI voice agent market was valued at $2.54 billion in 2025 and is projected to reach $35.24 billion by 2033, growing at a CAGR of 39% (Grand View Research). At the same time, WhatsApp has crossed 3.3 billion monthly active users, and more than 50 million businesses now use WhatsApp Business to reach them.

Combining these two trends makes sense for businesses that want to:

• Answer every call instantly. No hold times, no missed calls, no voicemail.
• Scale without headcount. Handle 1,000 concurrent calls per number (Meta's limit).
• Go global. AI agents speak multiple languages, perfect for WhatsApp's international user base.
• Keep conversations in one channel. Customers stay in WhatsApp, no app switching required.

How It Works

WhatsApp Business Calling routes calls directly between Meta and Telnyx, not through the PSTN.

When you connect an AI voice agent, the flow looks like this:

1. A WhatsApp user calls your business number
2. Telnyx receives the call and routes it to your Voice API application
3. The AI assistant answers, listens, and responds in natural speech
4. The conversation stays in WhatsApp, with full call recording, transcription, and analytics

For outbound calls, the flow reverses: your AI agent initiates a call to a WhatsApp user using a SIP dial string, and the user picks up inside their WhatsApp app.

Prerequisites

Before you start, you will need:

• A Telnyx account with a phone number
• Your business must be verified in Meta Business Manager
• A Telnyx AI Assistant configured

Step-by-Step Setup

Prefer to see it in action first? The two-minute walkthrough below shows the full flow, from enabling WhatsApp Calling in Mission Control to an AI agent answering a live inbound call. Then follow the step-by-step setup below to build it yourself.

📺 Watch the 2-minute walkthrough on YouTube

Step 1: Connect Your WhatsApp Business Account

In the Telnyx Mission Control Portal, navigate to Voice Suite and WhatsApp calling. Click "Connect WhatsApp Business"

Step 2: Associate Your Telnyx Number

Select the WhatsApp Business Account (WABA) you want to associate with WhatsApp Calling. Select the Telnyx phone number you want to enable for WhatsApp Calling. This is the number customers will see and call from inside WhatsApp.

Step 3: Review and Confirm

Review and confirm your WhatsApp configuration in Telnyx. Navigate to Voice Suite → WhatsApp Calling → Business Account — your WABA should now appear with an Active status.

For detailed setup instructions, see the Telnyx support guide on enabling WhatsApp Business Calling.

Step 4: Assign an AI Assistant

Create or select an AI Assistant in Mission Control. Configure it with:

• A system prompt that defines the agent's personality and knowledge
• Voice settings (language, speed, tone)
• Speech-to-Text and Text-to-Speech models
• Transfer rules (when to hand off to a human)

Step 5: Route Calls to Your AI Assistant

Create a Voice API application (or TeXML application) and set the AI Assistant as the answer handler. When a WhatsApp call comes in, it will be answered by your AI agent automatically.

Making WhatsApp Inbound Calls to Your AI Assistant

Once you created your AI assistant, all you need to do is connect the AI assistant to the WhatsApp enabled number.

Go to the calling tab in your AI assistant and assign the number. Then your AI assistant will answer the incoming calls.

Making WhatsApp Outbound Calls Using Your AI Assistant

To place a business-initiated call to a WhatsApp user, use the following dial string format:

<destination_number>@whatsapp-<your_telnyx_number>.sip.telnyx.com

For example, if your Telnyx number is +447418613982 and you want to call +447911123456:

[email protected]

You can use this SIP URI as the destination in any Voice API call, TeXML workflow, or SIP dial plan.

If you want to connect your AI assistant to this flow, you need to configure a Voice API application. For detailed setup instructions, see the Voice API Fundamentals document.

Then you can get the connection ID and assistant ID to build your call flow.

Using the:

Copy
curl --location 'https://api.telnyx.com/v2/calls' \
--header 'Accept: application/json' \
--header 'Content-Type: application/json' \
--header 'Authorization: Bearer ••••••' \
--data-raw '{
    "to":"+31639•••@whatsapp-4475•••.sip.telnyx.com",
    "from":"+4475•••",
    "connection_id":"2958•••",
    "assistant": {
        "id":"assistant-1e860114-c9ba-4ff9-9670-cc9a73884389"
    }
}'

Important: Calling Permissions

Before you can call a WhatsApp user, they must grant calling permission. There are three ways to obtain this:

• Send a permission request via the WhatsApp Cloud API (template or free-form message)
• Enable callbacks in Meta Business Suite (WhatsApp Manager > Phone > Call Settings > "Allow Callbacks"), which grants temporary permission after a user calls you first
• User-initiated permission from your WhatsApp Business profile (the user taps to grant access)

Meta monitors unanswered business-initiated calls. If too many consecutive calls go unanswered, your calling privilege may be restricted. Only call users who are expecting to hear from you.

Use Cases

Customer Support Automation

Businesses in LATAM and APAC use WhatsApp as their primary support channel. By adding AI voice agents, customers can call directly from WhatsApp and get instant answers to account questions, order status, or troubleshooting, without waiting for a human agent.

Appointment Reminders and Confirmations

Healthcare providers and service businesses can use outbound WhatsApp calls to remind patients of upcoming appointments. The AI agent confirms the time, offers to reschedule, and updates the calendar, all in a single call.

Lead Qualification

Sales teams can deploy AI agents to qualify inbound WhatsApp calls. The agent asks screening questions, captures lead details, and only transfers hot leads to a human sales rep.

Multilingual Support

With AI voice agents, one number can serve customers in dozens of languages. The agent detects the caller's language and responds accordingly, making it ideal for businesses operating across EMEA or APAC.

Pricing

WhatsApp Business Calling on Telnyx has straightforward pricing. You can view your specific rates on the WhatsApp Calling pricing page or in Mission Control under My Pricing.

What You Cannot Do

A few limitations to keep in mind:

• You cannot bridge WhatsApp calls to the PSTN. WhatsApp Calling is on-net to WhatsApp users only.
• The maximum concurrent call limit is 1,000 per business number.
• Business-initiated calls require user permission (see above).