LINE OA Appointment Booking Automation with n8n + OpenAI

Book appointments on LINE automatically—using n8n + OpenAI + Google Calendar

This LINE Official Account appointment booking automation lets customers schedule, reschedule, or cancel appointments by messaging your LINE OA. It uses OpenAI to understand booking requests, checks availability in Google Calendar, logs results to Google Sheets, and sends automated LINE confirmations and reminders.

What this workflow does

• Receives LINE messages via webhook and verifies the request signature before responding with a 200 for valid events.
• Understands customer intent with OpenAI: splits the webhook payload into individual text messages, then extracts whether the customer wants to book, cancel, or reschedule, plus the booking details.
• Validates service + time against opening hours. If required info is missing, the workflow asks follow-up questions in LINE.
• Checks availability in Google Calendar for the requested day. If the time is taken, it replies with up to three alternative time options using LINE quick-reply buttons.
• Creates/updates appointments in Google Calendar when a slot is available, and logs booking status + metadata to a Google Sheets “Bookings” tab.
• Sends confirmations and handles cancellations: confirms the appointment in LINE (and triggers an owner alert for new bookings). For cancellation requests, it deletes the calendar event and updates the booking as cancelled.
• Runs hourly reminders: checks Google Sheets for bookings starting within the next 24 hours, sends LINE reminders, and marks bookings as reminded.

Use cases

• A clinic or salon where clients message LINE to book/reschedule appointments without calling.
• A service business that needs real-time scheduling with opening-hours validation.
• Operations teams that want reminders automatically pushed through LINE before appointments.

Technical details

• n8n workflow logic/nodes: if, set, code, filter, switch, webhook
• LINE: webhook events + signature verification (Channel access tokens required)
• OpenAI: extracts intent and booking details from LINE text
• Google Calendar: availability checks + create/update/delete events
• Google Sheets: logs bookings to the “Bookings” tab and tracks reminder status

Setup note: In the LINE Developers Console, enable webhooks and generate a Channel access token.