# Automate WhatsApp booking system with OpenAI and Cal.com: n8n workflow

> Started by another system calling it, and works across Google Sheets. It puts OpenAI behind a retrieval step, so answers are drawn from documents you supply...

Source: https://millionrounds.com/workflow/automate-whatsapp-booking-system-with-openai-and-cal-com (Millionrounds; every figure on the page links to its filing or article)

[Automation library](https://millionrounds.com/workflows) · [Scheduling](https://millionrounds.com/workflows?category=Scheduling#library)

# Automate WhatsApp booking system with OpenAI and Cal.com

Started by another system calling it, and works across Google Sheets. It puts OpenAI behind a retrieval step, so answers are drawn from documents you supply rather than from the model alone. 22 steps, 2 branches: large, and worth reading before you trust it with anything live.

Large Calls a model: OpenAI Retrieval

[Download free](https://millionrounds.com/login?next=%2Fapp%2Fworkflow%2Fautomate-whatsapp-booking-system-with-openai-and-cal-com)

**22 steps** Large: read it before trusting it with anything live

**2** Branches: places the flow splits

**0** Loops or waits

**1** Service it connects to

## The flow

Starts it 5 Model 4 Logic 5 Service 8

The steps in the order they run, from what starts it.

- 1 **Webhook Trigger (WhatsApp Input)** Webhook *Starts it*
- 2 **LLM: GPT-4o Chat Model** Lm Chat Open Ai *Model*
- 3 **AI Conversation Memory** Memory Buffer Window *Model*
- 4 **Create New Prospect in Google Sheet** Google Sheets Tool *Service*
- 5 **Update Prospect with Booking Details** Google Sheets Tool *Service*
- 6 **Fetch Available Time Slots** Tool Http Request *Model*
- 7 **Trigger: Check Appointments Every Hour** Schedule trigger *Starts it*
- 8 **Switch: Confirm vs Chat Flow** Switch *Logic*
- 9 **AI Booking Assistant (Dr Firas)** Agent *Model*
- 10 **Read Upcoming Appointments from Sheet** Google Sheets *Service*
- 11 **Retrieve Prospect Details** Google Sheets *Service*
- 12 **Send Response to WhatsApp** Respond To Webhook *Starts it*
- 13 **Filter Appointments Within Next 2 Hours** Code *Logic*
- 14 **Normalize Booking Time (UTC Format)** Code *Logic*
- 15 **Send SMS Reminder** Sms77 *Service*
- 16 **Send Booking** Http Request *Service*
- 17 **Mark SMS as Sent in Sheet** Google Sheets *Service*
- 18 **Format Date for Readability (Display)** Code *Logic*
- 19 **Check Booking Status (Success or Error)** Switch *Logic*
- 20 **Webhook Response: Booking Confirmed** Respond To Webhook *Starts it*
- 21 **Webhook Response: Booking Failed** Respond To Webhook *Starts it*
- 22 **Mark Booking as Confirmed in Sheet** Google Sheets *Service*

## How it's built

- **Starts on:** Another system calling it
- **Steps:** 22, with 2 branches
- **Size:** Large: read it before trusting it with anything live
- **Connects to:** Google Sheets
- **Model:** OpenAI
- **Retrieval:** Answers are drawn from documents you supply, not from the model alone

## Questions

What does it need to run?

An n8n account, plus your own Google Sheets account, and a key for OpenAI. You connect your own accounts after importing it; none are included.

What starts it?

It starts on another system calling it.

Does it use AI?

Yes. It calls OpenAI. Its answers draw on documents you give it, not on the model alone. Model calls are billed by the provider, not by n8n.

How long does it take to set up?

Take your time. At 22 steps it is large: read it before trusting it with anything live.

How do I import it?

Copy the workflow, open a new workflow in n8n and paste. The steps appear on the canvas, ready for your own accounts.

**Before you run it**

Nothing here has been tested by us. It is somebody's working automation, read and described from its own steps. Treat the connections it wants as a list of accounts it will touch, and read the 22 steps before you point it at anything that matters.

## Run it in n8n

- **Create your n8n account** Free to start. n8n is where the workflow runs. [Create an n8n account ↗](https://millionrounds.com/n8n)
- **Download the workflow** Free with a Millionrounds account. [Download free](https://millionrounds.com/login?next=%2Fapp%2Fworkflow%2Fautomate-whatsapp-booking-system-with-openai-and-cal-com)
- **Paste it into n8n** Open a new workflow in n8n and paste. Then connect your own accounts.

Stored with the author's traces removed: canvas notes, instance identifiers, saved credential names and any live document they had left behind.

## Connects to

Each opens the other workflows that use it.

[Google Sheets](https://millionrounds.com/workflows?service=Google+Sheets#library)

## Workflows like it

Also scheduling, with the same services where possible, closest in size first.

- [**Handle WhatsApp event bookings with OpenAI and Google Sheets** 22 steps · calls a model · Google Sheets, n8n data table](https://millionrounds.com/workflow/handle-whatsapp-event-bookings-with-openai-and-google-sheets)
- [**Telegram AI Personal Assistant with Gemini and Tools** 22 steps · calls a model · Gmail, Google Calendar](https://millionrounds.com/workflow/telegram-ai-personal-assistant-with-gemini-and-tools)
- [**WhatsApp AI assistant for Q&A & bookings with Gemini** 22 steps · calls a model · Google Drive, Google Sheets](https://millionrounds.com/workflow/whatsapp-ai-assistant-for-q-and-a-and-bookings-with-gemini)
- [**Generate and schedule SEO blog posts with Groq** 22 steps · Google Drive, Google Sheets](https://millionrounds.com/workflow/generate-and-schedule-seo-blog-posts-with-groq)
- [**AI multi-agent executive team for entrepreneurs with Gemini** 21 steps · calls a model · Gmail, Google Calendar](https://millionrounds.com/workflow/ai-multi-agent-executive-team-for-entrepreneurs-with-gemini)
- [**AI travel concierge: 7-day planner & daily outfit advisor** 23 steps · calls a model · Google Calendar, Google Sheets](https://millionrounds.com/workflow/ai-travel-concierge-7-day-planner-and-daily-outfit-advisor)