Building AI Belle: Your AI-Powered Outbound Call Agent in 10 Minutes

Welcome to the no-code build guide for AI Belle—your outbound call agent that dials, speaks, listens, and logs without you lifting a finger.

🌊 Live Demo

Watch the full build and demo video here:

🛠️ What You Need

• n8n instance (self-hosted or cloud w/ credentials manager) – Try n8n (free trial – affiliate link)

• Google Sheet with FirstName, PhoneE164, Status

• Ultravox account (for the AI voice agent)

• Twilio account (w/ AU voice-capable number)

• Basic JSON skills + a text editor

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✅ Step-by-Step Setup

1. Import the n8n Workflow

• Download the outbound.json file (linked below).

• Save and import it into n8n via File > Import from File.

2. Set the Trigger

• Start with a manual trigger to test your workflow.

• Later you can switch to a schedule (e.g., every 5 minutes) or webhook.

3. Connect Google Sheets

• Set up a Google Sheets node to pull the next lead from your list.

• Your sheet should include columns like FirstName, PhoneE164, and Status.

• Ensure your n8n credentials are authorized and connected properly.

4. Create an Ultravox Agent

• In the Ultravox dashboard, create a new agent.

• Choose a voice, disable memory/tools, and write a brief system prompt (e.g., for Belle calling about solar rebates).

• Copy the Agent ID for later use in your workflow.

5. Spin Up a Voice Session

• Use an HTTP request node to create a WebSocket session with Ultravox.

• Provide the Agent ID and necessary parameters.

• This returns a session URL you'll use in the TwiML.

6. Set Runtime Variables

• Capture the lead's name, number, and the Ultravox session URL.

• These will be used to personalize the call.

7. Prepare the TwiML

• Build a short XML snippet that tells Twilio to dial the lead and connect to the Ultravox session.

8. Place the Call

• Use the Twilio node to initiate the outbound call.

• Use your Twilio number for the From field and the lead's number for To.

9. Run a Test

• Execute the workflow manually.

• You should receive a real call with Belle greeting you by name.

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🔄 Optional: Batch Campaigns

• Replace the manual trigger with a scheduled Cron trigger.

• Add a "Split In Batches" node to control how many concurrent calls are launched (e.g., batches of 5).

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🔑 Troubleshooting Tips

• Make sure Twilio numbers include the country code and + prefix.

• If your Ultravox session fails, double-check your Agent ID and credentials.

• If you're getting errors with the JSON or HTTP request, try removing optional parameters or validating the structure.

• Share your Google Sheet with the service account used in n8n.

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🚀 What’s Next?

• Add a follow-up node to update call status in Google Sheets.

• Sync transcripts or call logs to your CRM.

• Set business-hour guardrails or include a Do-Not-Call check.

• Swap Sheets for Airtable or a Postgres DB.