Retell AI integration

Retell uses two webhook flows:

1. Function-call webhook for live tool execution during a call
2. Post-call webhook for call-completion events

Endpoints

• Function calls: POST https://app.hiredispatcher.com/api/webhooks/retell/function-call
• Post-call events: POST https://app.hiredispatcher.com/api/webhooks/retell/call-complete

Authentication

Both endpoints require:

• x-retell-signature

Unsigned or invalidly signed requests are rejected.

Function Tools

check_availability

Args

{ "date": "2026-03-15", "serviceType": "HVAC Repair" }

Response

{
  "availableSlots": [
    { "time": "9:00 AM", "technician": "Mike Rodriguez" }
  ]
}

book_job

Args

{
  "date": "2026-03-15",
  "time": "09:00",
  "serviceType": "HVAC Repair",
  "customerName": "John Smith",
  "customerPhone": "+15551234567",
  "urgency": "routine"
}

Response

{ "confirmed": true, "dispatchRequestId": "dsp_123", "message": "Appointment booked." }

Additional supported tools

• lookup_customer
• create_customer
• get_service_types
• get_business_hours
• transfer_call

Function-Call Request Shape

{
  "name": "book_job",
  "args": { "date": "2026-03-15", "time": "09:00", "serviceType": "HVAC Repair" },
  "call": {
    "call_id": "call_abc123",
    "agent_id": "agent_789",
    "from_number": "+15551234567"
  }
}

Post-Call Webhook Example

{
  "event": "call_ended",
  "call": {
    "call_id": "call_abc123",
    "agent_id": "agent_789",
    "from_number": "+15551234567",
    "transcript": "...",
    "recording_url": "https://..."
  }
}

Testing

Run a Retell test call and verify both function-call responses and post-call webhook deliveries.