Retell

Connect your Retell AI agents to KrosAI phone numbers for emerging market coverage.

Overview

Retell AI provides voice agents with natural conversation capabilities. KrosAI enables routing calls from African and Middle Eastern phone numbers to Retell agents.

Prerequisites

• KrosAI account with verified KYC

• Retell account with an agent created

• At least one KrosAI phone number

Setup Steps

1

Get Your Retell Agent ID

• Log into your Retell Dashboard

• Navigate to Agents

• Select your agent

• Copy the Agent ID

2

Connect Retell in KrosAI

• Go to Settings → Integrations in your KrosAI Dashboard

• Click Connect next to Retell

• Enter your Retell API Key

• Click Save & Test

3

Create a Retell Endpoint

Create endpoint (curl)

curl -X POST "https://api.krosai.com/v1/endpoints" \
  -H "x-api-key: kros_live_your_key" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Retell Booking Agent",
    "type": "agent",
    "url": "sip:[email protected]",
    "provider_config": {
      "provider": "retell",
      "agent_id": "your-retell-agent-id"
    }
  }'

4

Attach to Phone Number

Attach endpoint to phone number (curl)

curl -X PATCH "https://api.krosai.com/v1/phone-numbers/pn_abc123" \
  -H "x-api-key: kros_live_your_key" \
  -H "Content-Type: application/json" \
  -d '{
    "endpoint_id": "ep_retell_xyz"
  }'

Configuration Options

Provider Config Fields

Field	Required	Description
agent_id	Yes	Your Retell agent ID
retell_phone_number	No	Retell phone number for outbound (optional)

Outbound Calls

Initiate outbound call (curl)

curl -X POST "https://api.krosai.com/v1/outbound-calls" \
  -H "x-api-key: kros_live_your_key" \
  -H "Content-Type: application/json" \
  -d '{
    "from_number": "[phone]",
    "to_number": "[phone]",
    "endpoint_id": "ep_retell_xyz",
    "metadata": {
      "appointment_id": "apt_123"
    }
  }'

Dynamic Variables

Pass dynamic data to your Retell agent:

Outbound call with dynamic variables (curl)

curl -X POST "https://api.krosai.com/v1/outbound-calls" \
  -H "x-api-key: kros_live_your_key" \
  -H "Content-Type: application/json" \
  -d '{
    "from_number": "[phone]",
    "to_number": "[phone]",
    "endpoint_id": "ep_retell_xyz",
    "metadata": {
      "retell_dynamic_variables": {
        "customer_name": "John Smith",
        "appointment_time": "2:00 PM",
        "location": "Lagos Office"
      }
    }
  }'

Webhooks

Receive call events including Retell-specific data:

{
  "event": "call.completed",
  "call_id": "call_abc123",
  "direction": "outbound",
  "from_number": "[phone]",
  "to_number": "[phone]",
  "duration": 245,
  "provider": "retell",
  "agent_id": "agent_123",
  "transcript": "[Agent]: Hello! I'm calling to confirm your appointment...",
  "call_analysis": {
    "sentiment": "positive",
    "outcome": "confirmed"
  }
}

Troubleshooting

Call Not Connecting

• Verify your Retell API key is valid

• Check the agent ID exists in Retell

• Ensure your Retell account has sufficient credits

• Review call events in the KrosAI Dashboard

Audio Quality Issues

• Check network connectivity

• Review Retell's voice settings

• Verify audio codec compatibility (Opus recommended)

Agent Not Following Script

• Test the agent directly in Retell

• Check your prompt configuration

• Verify custom LLM settings