Senior Full-Stack Engineer — AI Voice Receptionist Platform

About the Project We're building an AI-powered 24/7 voice receptionist and lead management platform purpose-built for plumbing companies and local service businesses across the US. The product answers incoming phone calls using advanced voice AI, qualifies leads, books appointments, captures customer details, and syncs directly into existing CRMs. Technical Architecture: Frontend: Next.js, React, Tailwind CSS, shadcn/ui — responsive, rapid UI development Backend: Node.js/TypeScript, stateless API server — deployed on AWS ECS or Railway for horizontal scaling Database: PostgreSQL (ACID compliance, JSONB, GIN indexes for full-text search) Caching & Queues: Redis for real-time session management, rate limiting, job queues Telephony: Twilio Voice API Voice AI: OpenAI Realtime API / Retell.ai CRM Sync: OAuth 2.0, webhook-based bidirectional sync with retry logic Notifications: Twilio WhatsApp / 360dialog Business API Who We're Looking For Must-Have Experience: 3+ years full-stack development with Node.js/TypeScript and React/Next.js Production experience with Twilio APIs (Voice, WhatsApp, or similar telephony platforms) Built or integrated voice AI/conversational AI (OpenAI Realtime API, Retell.ai, Vapi, or similar) PostgreSQL at scale — including JSONB, indexing strategies, full-text search OAuth 2.0 and third-party API integrations — especially CRMs, field service management, or calendar platforms Redis for caching, session management, or job queues AWS or Railway deployment experience with containerized applications