WhatsApp Business Calling API: Enable Voice Calls for Customer Communication

Authentication Setup:

curl -X POST \
  https://graph.facebook.com/v18.0/phone_number_id/voice_calls \
  -H 'Authorization: Bearer YOUR_ACCESS_TOKEN' \
  -H 'Content-Type: application/json' \
  -d '{
    "messaging_product": "whatsapp",
    "to": "CUSTOMER_PHONE_NUMBER",
    "type": "voice_call",
    "voice_call": {
      "call_type": "business_initiated"
    }
  }'

Call Configuration Options:

• call_timeout: Maximum call duration (300-3600 seconds)
• ivr_menu: Interactive voice response configuration
• call_routing: Department or agent routing rules
• recording_enabled: Call recording preferences
• fallback_number: Backup contact for failed calls

Webhook Endpoint Setup:

POST /webhook/whatsapp-calling
Content-Type: application/json

{
  "object": "whatsapp_business_account",
  "entry": [{
    "id": "ENTRY_ID",
    "changes": [{
      "value": {
        "messaging_product": "whatsapp",
        "metadata": {
          "display_phone_number": "PHONE_NUMBER",
          "phone_number_id": "PHONE_NUMBER_ID"
        },
        "voice_calls": [{
          "from": "CUSTOMER_PHONE_NUMBER",
          "id": "CALL_ID",
          "timestamp": "TIMESTAMP",
          "status": "initiated|ringing|answered|ended",
          "duration": "CALL_DURATION_SECONDS"
        }]
      }
    }]
  }]
}

Event Handling:

• call_initiated: When customer starts a call
• call_ringing: Call is connecting to agent
• call_answered: Agent picks up the call
• call_ended: Call completed with duration data
• call_failed: Call failed with error details

Testing Checklist:

• ✅ Inbound call functionality from test numbers
• ✅ Outbound call permission request flow
• ✅ IVR menu navigation and routing
• ✅ Call quality and audio clarity
• ✅ Webhook event delivery and processing
• ✅ Error handling and fallback scenarios
• ✅ Analytics and reporting accuracy
• ✅ Mobile and desktop compatibility

Production Deployment:

# Environment Variables
WHATSAPP_ACCESS_TOKEN=your_production_token
WHATSAPP_PHONE_NUMBER_ID=your_phone_id
WEBHOOK_VERIFY_TOKEN=your_webhook_token
API_VERSION=v18.0

# Rate Limiting
MAX_CALLS_PER_MINUTE=100
MAX_CONCURRENT_CALLS=50

# Monitoring
CALL_QUALITY_THRESHOLD=4.0
ERROR_RATE_ALERT=5%