n8n Webhook for Phone Appointment Booking with ElevenLabs, Exotel & Cal.com

Book phone appointments automatically with an n8n webhook—powered by ElevenLabs, Exotel, and Cal.com

This n8n workflow exposes appointment webhooks that let a voice agent check availability and book time slots in Cal.com. It returns JSON responses for suggested times or booking confirmations—plus it provides a separate endpoint to connect Exotel to an ElevenLabs conversational agent.

What this workflow does

• Receives appointment requests via POST to /appointment-webhook, including a tool name and payload from the calling assistant.
• Availability check: when the request asks to check availability, it queries the Cal.com Slots API using the provided date range, event type, and the Asia/Kolkata time zone.
• Returns up to four suggested times: the workflow formats slot times into a maximum of four start time recommendations and replies with a JSON payload indicating whether slots are available.
• Booking creation: when the request asks to book an appointment, it creates a booking in Cal.com for the requested start time and attendee details (name, email, and phone).
• Confirms or explains errors: it returns a JSON success response containing the booking ID and start time, or a friendly error message if booking fails or the tool name is unrecognized.
• Exotel + ElevenLabs connection: it also responds to /exotel-stream with a WebSocket URL that Exotel uses to connect to an ElevenLabs Conversational AI agent.

Use cases

• Voice-based scheduling where callers ask for available appointment times and receive suggested slots.
• Automated appointment booking with Cal.com from a phone call—confirming the time and capturing contact details.
• SaaS teams deploying an n8n webhook to connect conversational AI (ElevenLabs) with telephony (Exotel) and scheduling (Cal.com).

Technical details

• n8n nodes: if, webhook, sticky note, http request, respond to webhook.
• Integrations: Cal.com (Slots API + booking creation) using a Cal.com API key in n8n credentials via HTTP Header Auth, including the required cal-api-version header.
• Configuration: update eventTypeId values to match the Cal.com event you want to offer.
• Webhooks: use production webhook URLs for /appointment-webhook and /exotel-stream in ElevenLabs.