Building AI Voice Agents with n8n and Retell AI: A Practical Guide

As someone who builds AI automation systems for businesses, I've found that combining n8n with voice AI platforms creates incredibly powerful solutions. Here's how you can get started.

The Architecture

Phone Call → Retell AI → Webhook → n8n → CRM/Database
                ↑                    ↓
                └──── Response ──────┘

Why This Stack?

• n8n: Open-source, self-hostable, powerful workflow automation
• Retell AI: Realistic voice synthesis, easy API integration
• Flexibility: Connect to any CRM, database, or API

Setting Up the Basics

1. Create a Retell AI Agent

First, set up your voice agent in Retell AI with:

• Voice selection
• Base prompt/personality
• Webhook URL (your n8n endpoint)

2. Create n8n Webhook

Your n8n workflow starts with a Webhook node that receives call data from Retell AI.

3. Process the Incoming Data

The webhook receives call data including:

• Caller phone number
• Transcript
• Intent detected
• Custom variables

4. Business Logic in n8n

Here's where the magic happens:

• Lead Qualification: Score the lead based on responses
• CRM Update: Push data to GoHighLevel, HubSpot, etc.
• Appointment Booking: Check calendar and book slots
• Notifications: Alert your team via Slack, email, SMS

5. Send Response Back

n8n can send dynamic responses back to Retell AI:

• Next questions to ask
• Appointment confirmation details
• Custom information from your database

Real Example: Dental Appointment Booking

1. Patient calls
2. AI greets and asks for name
3. n8n checks if existing patient in CRM
4. AI asks for preferred date/time
5. n8n checks availability in calendar
6. AI confirms appointment
7. n8n creates booking + sends confirmation SMS

Tips for Production

1. Error Handling: Always have fallback responses
2. Logging: Log every interaction for debugging
3. Testing: Test edge cases before going live
4. Human Handoff: Always have an option to reach a human

Conclusion

Building AI voice agents doesn't have to be complicated. With the right tools and architecture, you can create systems that handle real business calls effectively.

If you're building something similar or have questions, drop a comment below!

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I'm Mohammad Arham Ansari, Founder of Call Dental AI. We build AI automation systems for businesses.

🌐 mohammadarhamansari.com
🏢 calldental.ai
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