Automate WhatsApp Event Booking with n8n, OpenAI & Google Sheets

Turn WhatsApp event requests into instant bookings—automatically

This n8n workflow automates WhatsApp event booking end-to-end: it receives inbound messages via a WAHA webhook, answers with OpenAI using Postgres conversation memory and Google Sheets tools, and sends the response back through the WAHA API as a text or an image caption.

What this workflow does

• Receives WhatsApp messages via a POST webhook from your WAHA server.
• Loads the assistant system prompt from an n8n Data Table and verifies the message is addressed to your business WhatsApp chat ID.
• Maintains conversation context by storing the customer’s message (or outgoing team messages) into a shared chat history.
• Answers event and booking questions using OpenAI with Postgres-backed memory plus tools that:
  • Read your Google Sheets event calendar
  • Look up Instagram post details
  • Analyze images via a sub-workflow
  • Append confirmed bookings to Google Sheets
• Structures the agent output into fields indicating whether to reply, the reply text, and an optional image URL.
• Sends the customer response through the WAHA API as either a text message or an image with a caption.

Use cases

• Customers ask for event availability on WhatsApp and get instant confirmation.
• Support teams respond faster by letting the workflow handle FAQ-style booking questions.
• You manage bookings in Google Sheets while WhatsApp acts as the booking front door.

Technical details

• WAHA webhook (webhook endpoint) and WAHA API responses
• OpenAI for the assistant + structured output auto-fix
• Postgres conversation memory (table: whatsapp_chat_history)
• Google Sheets event calendar read/write (requires YOUR_GOOGLE_SHEET_ID)
• n8n nodes used include: webhook, if, set, data table, sticky note, http request

Best for: n8n users, automation engineers, and SaaS operators deploying WhatsApp-to-booking flows.