We are an agency looking for an experienced Voice AI automation expert to build a seamless appointment booking system for a barbershop client. The core of this project involves configuring a Vapi voice assistant and integrating it in real-time with GoHighLevel (GHL) and the client's custom calendar system. The AI must be able to check live calendar availability during the call, book the appointment, and sync the data across platforms. Key Responsibilities: • Configure and fine-tune a Vapi AI voice assistant to act as a front-desk receptionist with a natural, low-latency conversational flow. • Set up Webhooks and Tool/Function Calling in Vapi so the AI can query live availability from a custom third-party calendar system (GET requests) and book appointments (POST requests) mid-conversation. • Integrate Vapi with GoHighLevel (GHL) to log call summaries, update contact records, and trigger SMS/email automations. • Ensure the data syncs flawlessly between Vapi, the custom calendar API, and GHL. • Configure a BYO SIP Trunk connection in Vapi to route a local UAE VoIP number. Requirements: • Proven experience building and deploying production-ready conversational AI agents using Vapi. • Deep understanding of API integrations, JSON payloads, and Webhooks. (Experience with automation platforms like Make.com or n8n is highly preferred). • Experience working with GoHighLevel (GHL) workflows, custom values, and API. • Ability to read and execute custom API documentation to build the bridge between Vapi and the client's proprietary calendar. • Strong troubleshooting skills to minimize latency during live tool calls. Screening Questions (Please answer when applying): 1. Can you share a quick example, case study, or recording of a Vapi agent you've built that uses tool calling to fetch live data (like checking a calendar)? 2. How do you typically handle latency or prevent the AI from "timing out" when Vapi has to wait for a webhook response from an external server? 3. Briefly explain how you would structure the data flow between Vapi, a custom calendar API, and GoHighLevel.