Wadi Wheels: Architecture & Workflow Breakdown

At Hertz, I saw firsthand that car rental is an inventory-concurrency problem disguised as customer service. Here is how Wadi Wheels automates the entire loop from database lock to key handover. Database-Level Inventory (Zero Double-Booking) Most platforms subtract bookings from total cars. That fails in real life.

Turnaround Buffer: Enforces a mandatory 2-hour cleaning/inspection buffer between rentals directly in the database query. Atomic Concurrency: When a customer clicks Pay, a PostgreSQL advisory lock (pg_advisory_xact_lock) serializes requests per car class. Two people cannot book the last car at the same second. 2. Autonomous Assignment Engine The moment the 20 JOD demo deposit clears:

Vehicle Match: Automatically assigns a free, active car from the chosen class (e.g., Hyundai Tucson, plate 21-45872). Bay Allocation: Reserves a parking spot in Zone B (e.g., Bay B-1-2) with guaranteed spacing around the arrival time. Private Trip Token: Generates a secure, unguessable 24-byte hex token. No renter login or password required. 3. The Digital Boarding Pass (/trip/:token) Replaces the physical counter queue entirely:

Gate Pass QR: Scans at the Zone B pedestrian access barrier. Key Safe Pass + 6-digit PIN: Unlocks the secure lockbox column beside the vehicle. 4-Step Visual Route: Takes the renter step-by-step from Queen Alia arrivals directly to their driver’s seat. 4. Operations & AI Triage (TypeSafe Jev) Live Fleet View: Realtime dashboard tracks vehicles, active bays, and hours saved for staff. Smart Inquiry Inbox: Free-form WhatsApp or web messages (in English, Arabic, or Arabizi) are processed by TypeSafe Jev. Instant Decisioning: Flags urgency, topic (availability, price, dates), and language—then auto-generates a pre-filled booking link so staff can reply in one tap. Results Counter Wait Time: Reduced from 45 minutes to under 3 minutes. Staff Overhead: Eliminates midnight handovers and manual WhatsApp scheduling. Stack: TanStack Start (React 19 SSR), PostgreSQL (RLS), TypeSafe Jev AI, Tailwind CSS.