Baylio — AI Call Assistant for Auto Repair Shops

Status: MVP v2.1 — Live telephony wired. Ready for first paying customer.

Baylio is a multi-tenant SaaS platform that installs an AI receptionist into any auto repair shop. When a customer calls the shop's dedicated Baylio number, an ElevenLabs voice AI answers 24/7, books appointments, captures vehicle details, and intelligently upsells services. Shop owners see every call logged, transcribed, and analyzed in their dashboard.

Business model: $199–$599/month per shop. ~86% gross margins. Target: 29 shops = $10K MRR.

---

Architecture Overview

Customer Call
     │
     ▼
Twilio (telephony)
     │  POST /api/twilio/voice
     ▼
Baylio Server (Express + tRPC)
     │
     ├─ Hot Context Cache (in-memory, TTL 5min)
     │   └─ phone → shopId → ShopContext (name, hours, catalog, agent)
     │
     ├─ Prompt Compiler (3-stage reasoning)
     │   └─ symptom extraction → catalog mapping → offer generation
     │
     └─ ElevenLabs Conversational AI (WebSocket stream)
          │  wss://api.elevenlabs.io/v1/convai/conversation
          ▼
     AI Voice Agent (answers call, books appointment, upsells)
          │
          ▼ (call ends)
     Post-Call Pipeline (async)
          ├─ Transcription (Whisper)
          ├─ Intent classification (LLM)
          ├─ Usage metering
          └─ SMS recap → shop owner

---

Tech Stack

Layer	Technology
Framework	React 19 + TypeScript + Vite
API	tRPC 11 (end-to-end type safety)
Server	Express 4 + Node.js
Database	MySQL/TiDB via Drizzle ORM
Auth	Manus OAuth (JWT sessions)
Voice AI	ElevenLabs Conversational AI
Telephony	Twilio (Voice API + SMS)
Billing	Stripe (subscriptions + setup fees)
Styling	Tailwind CSS 4 + shadcn/ui

---

Repository Structure

baylio/
├── client/                     # React frontend
│   └── src/
│       ├── pages/              # 11 page-level components
│       │   ├── Landing.tsx         # Public sales page with ROI calculator
│       │   ├── Dashboard.tsx       # Shop owner main dashboard
│       │   ├── ShopDetail.tsx      # Per-shop overview + metrics
│       │   ├── ShopSettings.tsx    # Shop profile + Twilio provisioning
│       │   ├── AgentConfig.tsx     # AI voice agent configuration
│       │   ├── CallLogs.tsx        # Call history with filters
│       │   ├── Analytics.tsx       # Revenue recovery charts
│       │   ├── MissedCallAudit.tsx # 7-day missed call analysis
│       │   ├── Subscriptions.tsx   # Tier management + billing
│       │   └── Notifications.tsx   # In-app alerts
│       ├── components/
│       │   ├── DashboardLayout.tsx # Sidebar nav wrapper
│       │   └── ui/                 # shadcn/ui component library
│       └── lib/trpc.ts             # tRPC client binding
│
├── server/                     # Express backend
│   ├── _core/                  # Framework plumbing (do not edit)
│   │   ├── index.ts                # Server entry point
│   │   ├── env.ts                  # Environment variable registry
│   │   ├── trpc.ts                 # tRPC context + procedures
│   │   └── llm.ts                  # LLM helper (Claude/GPT)
│   │
│   ├── routers.ts              # Master tRPC router
│   ├── shopRouter.ts           # Shop CRUD + Twilio provisioning
│   ├── callRouter.ts           # Call logs + analytics
│   ├── subscriptionRouter.ts   # Tier management + usage
│   ├── notificationRouter.ts   # In-app alerts
│   ├── organizationRouter.ts   # Multi-location grouping
│   │
│   ├── middleware/
│   │   ├── twilioValidation.ts     # HMAC-SHA1 webhook signature check
│   │   └── tenantScope.ts          # Multi-tenant isolation middleware
│   │
│   ├── services/
│   │   ├── twilioWebhooks.ts       # Inbound call handler (TwiML)
│   │   ├── twilioProvisioning.ts   # Phone number purchase/release
│   │   ├── elevenLabsService.ts    # ElevenLabs agent provisioning
│   │   ├── contextCache.ts         # Hot cache for sub-second webhook response
│   │   ├── promptCompiler.ts       # 3-stage AI prompt generation
│   │   ├── postCallPipeline.ts     # Async transcription + analysis
│   │   ├── smsService.ts           # Post-call SMS recap
│   │   ├── auditService.ts         # Missed call audit engine
│   │   └── scorecardGenerator.ts   # PDF scorecard for sales
│   │
│   ├── stripe/
│   │   ├── stripeRouter.ts         # Checkout + billing portal tRPC
│   │   ├── stripeRoutes.ts         # Stripe webhook handler
│   │   └── products.ts             # Tier definitions ($199/$349/$599)
│   │
│   └── db.ts                   # Drizzle query helpers
│
├── drizzle/
│   ├── schema.ts               # 10-table database schema
│   └── relations.ts            # Drizzle table relations
│
├── shared/
│   ├── types.ts                # Shared TypeScript types
│   └── const.ts                # Shared constants
│
└── server/*.test.ts            # Vitest test files (59 tests)

---

Database Schema (10 Tables)

Table	Purpose
users	Shop owners (OAuth, role: admin/user)
organizations	Multi-location grouping
shops	Individual shop profiles + Twilio numbers
agent_configs	Per-shop AI voice agent settings
call_logs	Every inbound call record
transcripts	Call transcriptions
customers	Caller profiles (auto-built from calls)
subscriptions	Stripe subscription state per shop
usage_records	Per-call metering for overage billing
missed_call_audits	7-day audit data for sales demos

All tables include ownerId for multi-tenant row-level isolation.

---

Environment Variables

Variable	Required	Description
DATABASE_URL	Yes	MySQL/TiDB connection string
JWT_SECRET	Yes	Session cookie signing key
TWILIO_ACCOUNT_SID	Yes	Twilio Account SID (ACxxxxxxxx)
TWILIO_AUTH_TOKEN	Yes	Twilio Auth Token (32-char hex)
ELEVENLABS_API_KEY	Yes	ElevenLabs API key
STRIPE_SECRET_KEY	Yes	Stripe secret key
STRIPE_WEBHOOK_SECRET	Yes	Stripe webhook signing secret
TWILIO_VALIDATION_ENABLED	No	Set to false to disable webhook signature validation (dev only)

---

Key Design Decisions

1. No DB Writes During Live Calls

The /api/twilio/voice webhook must respond in under 2 seconds or Twilio drops the call. All database writes happen asynchronously after the call ends via the post-call pipeline.

2. Hot Context Cache

Shop configuration (name, hours, service catalog, agent ID) is cached in memory with a 5-minute TTL. This eliminates DB queries during live webhook handling.

3. Tenant Isolation via ownerId

MySQL/TiDB has no native row-level security. Every child table includes an ownerId column that is always filtered in queries. The tenantScope middleware injects ctx.tenantId into every tRPC procedure.

4. Twilio Webhook Validation

All /api/twilio/* routes are protected by HMAC-SHA1 signature validation. In development, this runs in logOnly mode. In production, invalid signatures return 403 (toll fraud prevention).

5. 3-Stage Prompt Compilation

Rather than a static system prompt, Baylio compiles a fresh prompt per call:

1. Symptom extraction — what is the customer describing?
2. Catalog mapping — which services in the shop's catalog match?
3. Offer generation — what upsell makes sense at this confidence level?

---

Running Locally

# Install dependencies
pnpm install

# Run development server
pnpm dev

# Run tests
pnpm test

# Generate DB migration
pnpm drizzle-kit generate

# Push schema to DB
pnpm drizzle-kit push

---

Subscription Tiers

Tier	Price	Minutes Included	Overage
Starter	$199/mo	300 min	$0.05/min
Pro	$349/mo	750 min	$0.04/min
Elite	$599/mo	2,000 min	$0.03/min

Setup fee: $299 one-time (waived for annual prepay).

---

Live Infrastructure

Service	Account
Twilio	REDACTED_TWILIO_SID (Pay-as-you-go)
ElevenLabs	REDACTED_ELEVENLABS_AGENT_ID (Baylio agent)
Test number	(XXX) XXX-XXXX / +1REDACTED
GitHub	github.com/asayeed95/baylio (private)

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Migration Path to Supabase + Vercel (Future)

When revenue justifies the migration (target: 100+ shops), the following changes are needed:

1. Schema: Replace mysqlTable with pgTable in drizzle/schema.ts. Update all int → serial for auto-increment PKs.
2. Connection: Update DATABASE_URL to Supabase PostgreSQL connection string.
3. RLS: Implement native Supabase Row Level Security policies to replace application-level ownerId filtering.
4. Hosting: Configure Vercel project, set all env vars, connect GitHub repo for auto-deploy.
5. Estimated effort: 4-6 hours with Claude Code assistance.

See MIGRATION.md for the detailed step-by-step guide.