Automated Phone Interview Evaluation with Vapi, GPT-4o & Google Sheets

Description

This n8n workflow template automatically processes phone interview transcripts using AI to evaluate candidates against specific criteria and saves the results to Google Sheets. Perfect for HR departments, recruitment agencies, or any business conducting phone screenings.

What This Workflow Does

This automated workflow:
Receives phone interview transcripts via webhook
Uses OpenAI GPT models to analyze candidate responses against predefined qualification criteria
Extracts key information (name, phone, location, qualification status)
Automatically saves structured results to a Google Sheet for easy review and follow-up

The workflow is specifically designed for driving job interviews but can be easily adapted for any position with custom evaluation criteria.

Tools & Services Used

N8N** - Workflow automation platform
OpenAI API** - AI-powered transcript analysis (GPT-4o-mini)
Google Sheets** - Data storage and management
Webhook** - Receiving transcript data

Prerequisites

Before implementing this workflow, you'll need:

N8N Instance - Self-hosted or cloud version
OpenAI API Account - For AI transcript processing
Google Account - For Google Sheets integration
Phone Interview System - That can send webhooks (like Vapi.ai)

Step-by-Step Setup Instructions

Step 1: Set Up OpenAI API Access

Visit OpenAI's API platform
Create an account or log in
Navigate to API Keys section
Generate a new API key
Copy and securely store your API key

Step 2: Create Your Google Sheet

Option 1: Use Our Pre-Made Template (Recommended)
Copy our template: Driver Interview Results Template
Click "File" → "Make a copy" to create your own version
Rename it as desired
Copy your new sheet's URL - you'll need this for the workflow

Option 2: Create From Scratch
Go to Google Sheets
Create a new spreadsheet
Name it "Driver Interview Results" (or your preferred name)
Set up the following column headers in row 1:
A1: name
B1: phone
C1: cityState
D1: qualifies
E1: reasoning
Copy the Google Sheet URL - you'll need this for the workflow

Step 3: Import and Configure the N8N Workflow

Import the Workflow
Copy the workflow JSON from the template
In your N8N instance, go to Workflows → Import from JSON
Paste the JSON and import

Configure OpenAI Credentials
Click on either "OpenAI Chat Model" node
Set up credentials using your OpenAI API key
Test the connection to ensure it works

Configure Google Sheets Integration
Click on the "Save to Google Sheets" node
Set up Google Sheets OAuth2 credentials
Select your spreadsheet from the dropdown
Choose the correct sheet (usually "Sheet1")

Update the Webhook
Click on the "Webhook" node
Note the webhook URL that n8n generates
This URL will receive your transcript data

Step 4: Customize Evaluation Criteria

The workflow includes predefined criteria for a Massachusetts driving job. To customize for your needs:

Click on the "Evaluate Candidate" node
Modify the system message to include your specific requirements
Update the evaluation criteria checklist
Adjust the JSON output format if needed

Current Evaluation Criteria:
Valid Massachusetts driver's license
No felony convictions
Clean driving record (no recent tickets/accidents)
Willing to complete background check
Can pass drug test (including marijuana)
Available full-time Monday-Friday
Lives in Massachusetts

Step 5: Connect to Vapi.ai (Phone Interview System)

This workflow is specifically designed to work with Vapi.ai's phone interview system. Here's how to connect it:

Setting Up the Vapi Integration

Copy Your N8N Webhook URL
In your n8n workflow, click on the "Webhook" node
Copy the webhook URL (it should look like: https://your-n8n-instance.com/webhook-test/351ffe7c-69f2-4657-b593-c848d59205c0)

Configure Your Vapi Assistant
Log into your Vapi.ai dashboard
Create or edit your phone interview assistant
In the assistant settings, find the "Server" section
Set the Server URL to your n8n webhook URL
Set timeout to 20 seconds (as configured in the workflow)

Configure Server Messages
In your Vapi assistant settings, enable these server messages:
end-of-call-report
transcript[transcriptType="final"]

Set Up the Interview Script
Use the provided interview script in your Vapi assistant (found in the workflow's system message)
This ensures consistent data collection for the AI evaluation

Expected Data Format from Vapi

The workflow expects Vapi to send data in this specific format:

{
"body": {
"message": {
"artifact": {
"transcript": "AI: Hi. Are you interested in driving for Bank of Transport?\nUser: Yes.\nAI: Great. Before we go further..."
}
}
}
}

Vapi Configuration Checklist

✅ Webhook URL set in Vapi assistant server settings
✅ Server messages enabled: end-of-call-report, transcript[transcriptType="final"]
✅ Interview script configured in assistant
✅ Assistant set to send webhooks on call completion

Alternative Phone Systems

If you're not using Vapi.ai, you can adapt this workflow for other phone systems by:
Modifying the "Edit Fields2" node to extract transcripts from your system's data format
Updating the webhook data structure expectations
Ensuring your phone system sends the complete interview transcript

Step 6: Test the Workflow

Test with Sample Data
Use the "Execute Workflow" button with test data
Verify that data appears correctly in your Google Sheet
Check that the AI evaluation logic works as expected

End-to-End Testing
Send a test webhook with a real transcript
Monitor each step of the workflow
Confirm the final result is saved to Google Sheets

Workflow Node Breakdown

Webhook - Receives transcript data from your phone system
Edit Fields2 - Extracts the transcript from the incoming data
Evaluate Candidate - AI analysis using GPT-4o-mini to assess qualification
Convert to JSON - Ensures proper JSON formatting with structured output parser
Save to Google Sheets - Automatically logs results to your spreadsheet

Customization Options

Modify Evaluation Criteria
Edit the system prompt in the "Evaluate Candidate" node
Add or remove qualification requirements
Adjust the scoring logic

Change Output Format
Modify the JSON schema in the "Structured Output Parser" node
Update Google Sheets column mapping accordingly

Add Additional Processing
Insert nodes for email notifications
Add Slack/Discord alerts for qualified candidates
Integrate with your CRM or ATS system

Troubleshooting

Common Issues:
OpenAI API Errors**: Check API key validity and billing status
Google Sheets Not Updating**: Verify OAuth permissions and sheet access
Webhook Not Receiving Data**: Confirm URL and POST format from your phone system
AI Evaluation Inconsistencies**: Refine the system prompt with more specific criteria

Usage Tips

Monitor Token Usage**: OpenAI charges per token, so monitor your usage
Regular Review**: Periodically review AI evaluations for accuracy
Backup Data**: Export Google Sheets data regularly for backup
Privacy Compliance**: Ensure transcript handling complies with local privacy laws

Need Help with Implementation?

For professional setup, customization, or troubleshooting of this workflow, contact:

Robert - Ynteractive Solutions
Email**: [email protected]
Website**: www.ynteractive.com
LinkedIn**: linkedin.com/in/robert-interactive

Specializing in AI-powered workflow automation, business process optimization, and custom integration solutions.