Liveagent.dev - Live Voice Agent for Booking and Reservation

Receive Booking and Reservation 24/7

Comment

Inspiration

I've experienced this frustration firsthand — trying to book a table at a restaurant over WhatsApp, waiting hours for a reply that never comes, and eventually just picking another place. I had the same thing happen trying to book a dentist appointment to check my teeth — slow replies, no confirmation, and eventually giving up and finding a different clinic. In both cases, the businesses lost a paying customer not because of bad service, but because no one was available to answer.

These aren't edge cases — they're everyday frustrations that cost businesses real customers. Staff are busy serving existing customers, phone lines go to voicemail, and chat messages pile up unanswered.

I realized that the Gemini Live API's native bidirectional audio streaming could solve this problem in a way that text-based chatbots never could: a voice agent that sounds natural, understands context, and can actually do things — like check real-time availability and create bookings on Google Calendar — all through a seamless voice conversation. No more waiting for a text reply. No more phone tag. Just click, talk, and book. I wanted to move beyond the "text box" paradigm and build something that feels like talking to a real, competent receptionist — one that's available 24/7 and never puts you on hold.

What it does

Liveagent.dev is a platform that lets any business create and deploy an AI-powered voice agent that handles booking and reservation calls in real-time. Here's how it works:

  • Business owners sign in to a dashboard, configure their agent (business type, operating hours, voice persona, booking rules, resource capacity), and connect their Google Calendar via OAuth.
  • Customers interact with the agent through an embeddable voice widget on the business's website. They simply click a button and start talking — no forms, no typing, no hold music, no waiting for a chat reply.
  • The agent carries on a natural voice conversation powered by Gemini 2.5 Flash Live (native audio). It checks real-time availability, suggests open time slots, creates bookings, handles rescheduling and cancellations, and sends calendar invites — all mid-conversation using Gemini's function calling.
  • After the call, the business owner can review full conversation transcripts, analytics (call volume, booking rates, average duration), and manage upcoming reservations — all from the dashboard.

It supports 8 different voice personas, configurable operating hours per day, resource management (tables, rooms, courts, chairs), and works for a wide range of business types including restaurants, salons, medical clinics, spas, fitness studios, and more.

How I built it

I built Liveagent entirely solo, architecting it as a monorepo with three services, all deployed on Google Cloud Run:

  1. Agent Service (Fastify 5) — The core voice engine. It manages WebSocket connections from clients, streams PCM audio bidirectionally with the Gemini 2.5 Flash Live API using the @google/genai SDK, and executes function calls (check availability, create/reschedule/cancel bookings, send calendar invites) against the Google Calendar API via OAuth 2.0.

  2. Web Dashboard (Next.js 15 / React 19) — Where business owners configure agents, connect Google Calendar, view conversation transcripts, and monitor analytics. Uses iron-session for auth, TanStack Query for data fetching, and shadcn/ui for the interface.

  3. Embeddable Widget (Next.js 15) — A lightweight voice widget that any website can embed with a single <script> tag. It captures microphone audio via the Web Audio API, encodes it to PCM 16kHz, and streams it over WebSocket to the agent service. It also renders a live transcript and booking confirmation cards.

  4. Call App (Next.js 15) — A standalone, WhatsApp-style full-screen calling interface accessible via direct URL (e.g., call.liveagent.dev/joes-barbershop). Businesses set a unique username in the dashboard, and customers can call the agent without visiting the business's website. Features animated waveform visualization, booking cards, and a mobile-optimized dark UI.

All three services share a PostgreSQL database (Cloud SQL) via Prisma ORM, and common code lives in shared packages (UI components, constants, DB client). Infrastructure is provisioned with Terraform and deployed via Cloud Build to Google Artifact Registry and Cloud Run.

The voice pipeline works like this: Widget captures audio → WebSocket → Agent service → Gemini Live API (bidirectional streaming) → Function calling for calendar operations → Audio response streamed back → Widget plays audio. The entire round-trip feels conversational, with support for barge-in (interruption) via Gemini's built-in Voice Activity Detection.

Challenges I ran into

  • Calendar resource management — Handling concurrent bookings for limited resources (e.g., 10 tables at a restaurant) required building a resource assignment system on top of Google Calendar's freebusy API, using extended properties to track which resource is assigned to which booking.
  • Function calling mid-conversation — When Gemini calls a tool (like check_availability), the voice stream pauses while the function executes. Making this feel natural — so the agent says something like "Let me check that for you" before the pause — required careful prompt engineering in the system instructions.

Accomplishments that I'm proud of

  • End-to-end voice booking in under 60 seconds — A customer can call, check availability, book a time slot, and receive a Google Calendar invite, all through natural conversation, in under a minute.
  • One-script embed — Any business can add the voice agent to their website with a single <script> tag, no technical expertise required.
  • Production-grade infrastructure — Full Terraform IaC, Cloud Run auto-scaling, Secret Manager integration, and multi-stage Docker builds. This isn't a demo — it's deployable.
  • Seamless Gemini function calling — The agent naturally weaves tool calls into conversation flow. It checks availability, creates bookings, and sends invites without the user ever feeling like they're interacting with an API.
  • Support for diverse business types — From restaurants to medical clinics to tennis courts, the system handles different resource types, capacity models, and booking durations.

What I learned

  • Gemini's native audio mode is a game-changer — Compared to speech-to-text → LLM → text-to-speech pipelines, Gemini Live's native audio streaming dramatically reduces latency and produces more natural conversations. The model understands tone, pauses, and conversational cues that get lost in transcription.

What's next for Liveagent.dev - Live Voice Agent for Booking and Reservation

  • Custom knowledge bases — Let businesses upload menus, service catalogs, and FAQs that the agent can reference during calls.
  • Analytics AI — Use Gemini to analyze conversation patterns and suggest improvements to agent configuration.

Built With

Share this project:

Updates