The Project Story
The Challenge
Businesses often lose prospective clients and suffer high customer support overhead because they cannot answer phone calls instantly, especially outside of regular business hours. Maintaining a round-the-clock human call center is financially prohibitive for small-to-medium businesses and marketing agencies.
The Solution
I built an automated phone assistant operating on telephony lines and web-browsers. The stack integrates Telnyx for SIP phone line routing, Vapi as the voice gateway, Deepgram for instant speech-to-text, and Groq for sub-second LLM query processing. A custom n8n backend is connected to automatically process call logs, schedule calendar appointments, and trigger CRM updates in real-time.
The Business Impact
The assistant resolved inbound support queries automatically, qualified leads on the fly, and enabled 24/7 call booking capabilities with zero missed calls. The setup achieved a human-like response latency of 500-750ms, allowing natural conversation flow.
System & Interface Showcase
Screenshots of the Vapi agent configuration, n8n telemetry pipelines, and voice assistant dashboard workspaces.
1. Telnyx Call Routing
2. Vapi AI Prompting & Tool Calling
3. n8n Workflow with Lead Qualification and Calendar Booking Logic
Architecture Overview
A low-latency, real-time voice synthesis and speech-to-text pipeline integrated into standard telecom systems.
- Telephony & SIP Trunking: Routed via Telnyx to map inbound telephone numbers.
- Voice Gateway & Orchestrator: Managed via Vapi to orchestrate and connect real-time audio streams.
- Real-Time Transcriber: Utilizes Deepgram for instant, low-latency speech-to-text conversion.
- AI Model & Conversational Brain: Powered by Groq (Llama-3) for sub-second response generation.
- Workflow Automation: Connected through n8n to trigger lead qualification and data syncing.
- Scheduling & Booking Engine: Powered by Cal.com (API v2) for real-time slot checking and meeting creation.
- Database & Storage: Hosted on Supabase for call logs, state persistence, and metrics.
System Diagram
User Call → Telephony/SIP Trunk (Telnyx) → Voice Gateway (Vapi)
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AI Brain (Groq/LLM) & Transcriber (Deepgram)
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Automation Engine (n8n)
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CRM & Booking Systems (Cal.com)
Technical Features
- Low-Latency Pipeline: Optimized audio streaming ensuring responses within 500-750ms.
- In-Browser WebRTC Demo: Prospective clients can test the assistant directly via browser without telephony costs (deployed in the Interactive Lab).
- Auto-Booking Integration: AI assistant schedules calendar bookings directly into CRMs via secure APIs.
- Call Logging: n8n cleans transcripts and stores structured summaries in Supabase.