WhatsApp Voice Agent with Twilio, VAPI, Google Calendar, Gmail & Supabase
This workflow turns WhatsApp voice messages into an AI assistant using Twilio, VAPI, and modular MCP servers. It handles scheduling, email, and knowledge queries all by voice.
🔎 How it works
- WhatsApp → Twilio → VAPI
- A WhatsApp Business number (via TwiML app) receives a voice message.
- Twilio streams the audio into VAPI for processing.
- VAPI → n8n Webhook
- VAPI interprets the intent and routes the request to the correct MCP server.
- MCP Servers in n8n
- 📅 Calendar MCP → create, fetch, update, delete Google Calendar events
- 📧 Gmail MCP → send confirmation or reminder emails
- 📚 Knowledge Base MCP → query Supabase Vector Store with OpenAI embeddings
- n8n → VAPI → WhatsApp
- n8n executes the task and returns the result via VAPI back to the user.
🛠️ How to use
- Import this workflow into your n8n instance.
- Configure a Twilio WhatsApp-enabled number and connect it to a TwiML app.
- Point the TwiML app to your VAPI project.
- Add credentials for Google Calendar, Gmail, Supabase, and OpenAI in n8n.
- Test by sending a WhatsApp voice command like:
- “Book a meeting tomorrow at 3pm”
- “Send a confirmation email to the client”
- “What’s included in the AI receptionist package?”
🎨 Customisation ideas
- Add more MCP servers (e.g. CRM, Notion, Slack).
- Swap Supabase for another vector database.
- Extend Gmail flows with templates or multiple senders.
- Adjust the VAPI assistant’s tone and role to fit your brand.
📌 Requirements
- Twilio WhatsApp-enabled number + TwiML app (verified in WhatsApp Manager)
- VAPI project (assistant configured)
- n8n instance (Cloud or self-hosted)
- Google Calendar & Gmail credentials
- Supabase project
- OpenAI API key
💡 Good to know
- Twilio must have a verified WhatsApp Business number.
- VAPI handles voice infra + intent routing ; n8n only executes actions.
- The design is modular —easy to expand with new MCP servers.
- Works best when tested with short, clear commands.
🚀 Use cases
- Hands-free scheduling with Google Calendar.
- Voice-triggered email confirmations & reminders.
- Conversational knowledge base access.
- Extendable to CRMs, team chat, or business workflows.
👉 With this setup, you get a scalable voice-first AI agent on WhatsApp that connects seamlessly to your business systems.
