The GoHighLevel integration empowers your Vapi voice agents to directly interact with your clients’ GoHighLevel calendars. Your agents can use a suite of tools to manage the appointment lifecycle: check if a contact already exists using the Get Contact tool, create new leads or clients with the Create Contact tool, query specific GHL calendars for open slots via the Check Availability tool, and secure appointments associated with a contact using the Create Event tool. This enables your voice agent to handle the entire booking process seamlessly within the GHL calendar that your agency or client already uses.
Before you can use the GoHighLevel integration, you need to:
First, you need to connect your GoHighLevel account to Vapi:
The authorization process will request access to your GoHighLevel account to manage contacts, calendars, and appointments.

After connecting your GoHighLevel account, create the tools:
calendarId. You can find the calendarId for each of your calendars in GoHighLevel by navigating to Settings > Calendars. Each calendar listed will display its unique ID.When creating an event in GoHighLevel, a contactId is required. Therefore,
if you plan to use the Create Event tool, you must also add the Get
Contact and Create Contact tools. This allows the assistant to first
retrieve an existing contact’s ID or create a new contact, and then use that
ID to schedule the event.

Now, add your chosen GoHighLevel tool(s) to your assistant. For an example scenario where you want your assistant to book appointments, including finding a suitable time and managing contact information, you would add all four tools: Get Contact, Create Contact, Check Availability, and Create Event.

After adding the GoHighLevel tools to your assistant, it’s crucial to provide a clear system prompt. This prompt guides the assistant on how and when to use each tool to achieve the desired workflow. For a typical appointment booking scenario, your system prompt instructs the AI on the sequence of operations and conditions for using each tool.
Here’s an example system prompt to guide your assistant. Remember to replace ghl_contact_get, ghl_contact_create, ghl_check_availability, and ghl_create_event with the exact names you gave your tools if they are different.
This tool uses both or one of the following fields to retrieve an existing contact:
email: The email address of the contact to search for.phone: The phone number of the contact to search for.This tool uses the following fields to create a new contact:
firstName: The first name of the contact.lastName: The last name of the contact.email: The email address of the contact.phone: The phone number of the contact.This tool uses the following fields to check for open appointment slots:
calendarId: The ID of the GoHighLevel calendar to check.startDate: The start of the time range to check for availability (epoch time in milliseconds).endDate: The end of the time range to check for availability (epoch time in milliseconds).timezone: The timezone for the availability check (e.g., “America/New_York”).This tool uses the following fields to book an appointment:
calendarId: The ID of the GoHighLevel calendar in which to create the event.contactId: The ID of the GoHighLevel contact to associate with the event.title: The title or summary for the calendar event.startTime: The start date and time for the event in ISO 8601 format.endTime: The end date and time for the event in ISO 8601 format.Here’s how the tools can be configured in your assistant’s JSON setup:
contactId. Ensure your assistant’s logic always fetches or creates a contact (using the getGHLContact and createGHLContact tools) before attempting to book an appointment with the createGHLEvent tool.