AI Voice Agent for Leads Reactivation

This project automates the process of reactivating inactive leads using an AI voice agent. The system targets business warm leads/prospects who previously showed interest but didn't convert—to help generate additional revenue. Instead of relying on less effective email campaigns, the AI voice agent makes personalized follow-up calls to re-engage leads, qualify them, or gather intent for the sales team. This approach is ideal for businesses with large lead databases and low conversion rates.

The Problem: Cold Leads and Missed Opportunities

Many businesses have a large database of warm leads - people who showed interest in the past but didn't buy. Maybe they filled out a form, attended a webinar, or even started a trial. These are potential customers, but they often go cold and are forgotten. Reaching out to them with emails often doesn't work well, and manually calling each one is time-consuming and expensive. This means lost revenue and missed opportunities to grow your business.

The Solution: AI Voice Agent for Lead Reactivation

This project offers a powerful solution: an AI voice agent that automatically calls your inactive leads to re-engage them. But it does more than just make calls. This AI system helps you understand why those leads went cold in the first place, giving you valuable insights to improve your entire sales process. Instead of relying solely on ineffective email campaigns, the system makes personalized calls to reactivate leads, qualify them, update your CRM, and provide actionable data on your sales pipeline. This means you can:

• Reactivate cold leads: Turn those old leads back into potential customers.
• Increase sales: Convert more leads into paying customers.
• Save time and resources: Automate the outreach process, freeing up your sales team.
• Improve lead qualification: the system analyzes conversations to identify high-potential leads.
• Uncover sales process bottlenecks: By analyzing conversations with lost leads, the AI can identify common reasons for disinterest. This could reveal issues like unclear messaging, pricing concerns, or missing features, helping you optimize your sales strategy and improve future conversion rates.
• Generate more revenue from existing leads

In short, this project not only helps you turn your inactive lead database into a source of new revenue but also provides valuable insights to improve your overall sales process by using the power of AI. It's ideal for businesses struggling with low conversion rates and looking for a scalable way to re-engage old leads and optimize their sales funnel.

How It Works

1. CRM Integrations Dead leads are imported from your CRM, whether it's Airtable, HubSpot, Google Sheets, or another system of your choice. The database includes key lead details (e.g., name, address, email) to personalize interactions without being overly intrusive.

2. Call Trigger A custom AI voice agent built on the VAPI platform initiates calls to the leads. Using a personalized script, the agent engages leads to gauge their interest and qualify them. The voice agent has also access to a scheduling tool connected to Google Calendar, enabling the agent to book follow-up appointments if a lead expresses interest.

3. Communication with VAPI During and after each call, VAPI sends data (such as call states, transcripts, recordings, and summaries) back to the server via a webhook. Two key webhook events are of interest:

   • Tool Calls: When the agent schedules a follow-up appointment with a lead using the integrated booking tool.
   • End-Call Report: A detailed report is sent at the end of each call, containing the transcript, cost, duration, and conversation messages. This data is used for the post-call analysis and CRM updates.

4. Lead Qualification and CRM Update Once the end-call report is received, the system triggers a post-call analysis function. This function leverages an AI agent (using GPT-4o or alternatives) to analyze the transcript, determine the lead's level of interest, and generate actionable notes for the sales team. Finally, the CRM is updated with all relevant call details, including the lead's status.

AI Voice Agent Frameworks

Several frameworks are available for building voice agents, and this repository includes the necessary code for the most popular options: VAPI, Retell AI, and OpenAI’s Real-Time API (not fully implemented yet).

• Both VAPI and Retell AI are no-code platforms that support a variety of LLMs providers and voice models for developing Voice AI agents, including OpenAI’s real-time APIs. They simplify the Voice agent development process, offering many features like direct telephony integration with Twilio, custom tool integration, interruption handling, and fallback responses during delays, etc.
• OpenAI’s Real-Time API (speech-to-speech model) is currently the fastest voice technology available. You can either use it via platforms like VAPI or Retell AI for convenience or integrate it directly using openai to avoid additional platform fees.

For this project, I used VAPI for the voice agent’s development, but, the code is designed to be adaptable and can be configured to work with Retell AI or OpenAI’s Real-Time API.

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API Integrations

• OpenAI: Uses GPT-4o models. Get API key here.
• Twilio: Handles phone calls. Obtain a Twilio number here.
• Airtable CRM: Connects to your Airtable contacts database. Sign up and create a contacts database with the required fields.
• HubSpot CRM: Integrates with HubSpot for managing your leads. Sign up for a HubSpot account, create a private app, and obtain an API key. Follow this tutorial for help.
• Google APIs: Used for accessing Google Calendar and Google Sheets (only when these are selected as CRM sources).
• Google Search Automation: Utilizes the Serper API for web searches. Get your API key here.

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Tech Stack

• LiteLLM: Offers easy access to multiple LLMs (GPT-4o, Claude, Gemini, etc) with standard output format.
• Vapi
• Retell AI
• OpenAI

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How to Run

Prerequisites

• Python 3.9+
• Account and API key for Vapi
• OpenAI API key (or alternative LLMs like Claude or Groq)
• Twilio phone number
• Google API credentials (for Google Calendar or sheets when used as leads database).
• Integration keys for CRM tools (Airtable, HubSpot) and other services (e.g., Serper API).
• NGROK installed

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Setup

1. Clone the repository:

   git clone https://github.com/kaymen99/leads-reactivation-with-AI-Voice-Agent.git  
   cd leads-reactivation-with-AI-Voice-Agent  

2. Set up a virtual environment and install dependencies:

   python -m venv venv  
   source venv/bin/activate  # For Windows: `venv\Scripts\activate`  
   pip install -r requirements.txt  

3. Configure environment variables:

   Copy the example environment file and update it with your API keys:

   cp .env.example .env  

   Open the .env file and fill in your API keys and other configurations.

4. Run the app server:

   Start the server application:

   python app.py  

   To expose the server publicly, use ngrok. Open a new terminal and run:

   ngrok http 8000  

   Copy the public URL generated by ngrok and update the SERVER_URL variable in your .env file.

5. Set up the voice agent:

   • Create the necessary tools for the voice agent in Vapi. For this project, we only have a single tool for booking appointements with Google Calendar. Run the provided script:

     python scripts/create_or_update_tool.py  

     This script will return a tool ID. Copy it for the next step.

   • Update the tool configuration in scripts/create_or_update_assistant.py by adding the tool ID to tool_ids_list. Then, create the assistant:

     python scripts/create_or_update_assistant.py  

     Copy the assisatnt id to your .env file (VAPI_ASSISTANT_ID).

     Note: The assistant configuration uses GPT-4o by default. You can switch to another supported LLM by modifying the configuration before running the script.

   • Import your Twilio phone number into Vapi. Ensure you have added your Twilio credentials (watch this quick tutorial), then run:

     python scripts/import_phone_number.py  

     Copy the Vapi phone number id to your .env file (VAPI_PHONE_ID).

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Testing the Automation

To test the setup, you can simulate a call to your own phone number:

1. Ensure the server is running and accessible.
2. Trigger the automation route /execute using Postman or directly via the API docs dashboard.
3. The automation expects a list of lead IDs. You can either specify specific IDs or leave it empty to fetch any new leads.
4. You should receive a call from the voice agent.

After the call, check the CRM for updates or view the call logs directly in the VAPI dashboard.

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Customizing the Automation

If you want to integrate another CRM or customize the behavior of the automation, please refer to the Customization Guide. The guide covers:

• Integrating Custom CRMs: Instructions for adding your CRM to the system by extending the base class.
• Customizing Lead Statuses: Learn how to modify the statuses used to filter and fetch leads.
• Updating CRM Fields: Tailor the automation to handle different CRM field names or additional fields.
• Customizing Prompts: Update the prompts used for AI voice agent and the post call analysis (all pormpts are in src/prompts.py).

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Contributing

Contributions are welcome! Please open an issue or submit a pull request for any improvements or features you’d like to see.

Contact

For questions or suggestions, contact me at [email protected].