Engium Team
Engium · Jun 27, 2026
ChatGPT now has over 200 million weekly users. With Engium's ChatGPT integration, your customers can book, reschedule, and cancel appointments directly inside a ChatGPT conversation — without visiting your website or downloading any app. This guide walks you through everything you need to set it up in under 15 minutes.
What You Need Before You Start
ChatGPT Plus subscription required
Creating a custom GPT requires a ChatGPT Plus plan ($20/month) or ChatGPT Pro ($100/month). The Free and Go plans do not have access to the GPT builder. You can subscribe at chatgpt.com/settings.
- 01.An active Engium account (any paid plan)
- 02.A ChatGPT Plus or Pro subscription ($20/month minimum)
- 03.Your Engium OpenAPI Spec URL — found in Settings → Integrations → ChatGPT
How the Integration Works
Engium exposes a live OpenAPI 3.1 spec at a unique URL per business. When a customer asks your ChatGPT assistant "book me a haircut for Friday at 3pm", ChatGPT calls Engium's booking API in real time, checks your live availability, and creates a confirmed booking — all within the chat window.
The assistant can also reschedule and cancel existing bookings, and answer questions about your services, hours, and pricing using the business info endpoint. No manual intervention required on your end.
What your customers can do inside ChatGPT
Check real-time availability, book appointments, reschedule existing bookings, cancel with their phone number for verification, and ask questions about your services and hours.
Step-by-Step Setup
The entire setup takes place in ChatGPT's GPT Builder. You do not need to write any code.
- 01.Go to Settings → Integrations → ChatGPT in your Engium dashboard and copy your OpenAPI Spec URL.
- 02.Sign in to chatgpt.com with your Plus account and open chatgpt.com/gpts/editor.
- 03.Click Create, give your GPT your business name and a short description (e.g. "Book appointments at Bloom Salon").
- 04.Click the Configure tab → scroll to Actions → Add actions → Import from URL → paste your Engium spec URL.
- 05.Set visibility to Anyone with a link, click Update, and share the link with your customers.
Tip: copy the spec URL before opening the GPT builder
Your browser may open the GPT builder in a new tab. Copy your OpenAPI Spec URL from Engium first so you can paste it directly into step 4 without switching tabs.
Using the ChatGPT Business Plan
If your team uses ChatGPT Business ($20/user/month, billed annually), custom GPTs are available and can be shared internally across your workspace. This is useful if you want staff to use a GPT to create bookings on behalf of customers during phone calls.
Testing Your Assistant
After saving, use the Preview pane in the GPT Builder to test a full booking flow. Try: "Do you have availability this Saturday afternoon?" and follow the conversation through to a confirmed booking. Check your Engium dashboard — the booking should appear within seconds.
Was this helpful?