OpenLine — AI Voice Receptionist

Small businesses lose real customers every time a call goes to voicemail. OpenLine is a voice receptionist built on the AssemblyAI Voice Agent API that actually answers — politely, instantly, and with real business knowledge. What it does: Callers can ask about services, pricing, location, and opening hours, then book a real appointment. OpenLine checks a live availability schedule, writes confirmed bookings into a local SQLite ledger, and confirms back to the caller by voice. If a caller needs a human, the agent records a message and flags a callback. How it's built: A FastAPI server holds the AssemblyAI API key and mints short-lived browser tokens via GET /v1/token, so the key never ships to the client. The browser connects to wss://agents.assemblyai.com/v1/ws, streams microphone audio as PCM16 through a Web Audio worklet, and plays the agent's synthesized voice back in real time. The stored agent (created through POST /v1/agents) carries a system prompt tuned for front-desk behavior plus client-side tools: get_business_profile, get_hours, get_services, check_availability, book_appointment, list_appointments, and take_message. The browser runs each tool call locally against deterministic JSON/SQLite data and returns tool.result — so every answer about hours or availability is real data, not a hallucination. Why it matters: This is the smallest real business workflow where a voice agent pays for itself — one missed booking can be worth more than a month of phone service. Everything runs locally with zero deployment friction, and the same tool layer drops into any small business by editing one JSON file.