Design a car rental booking system

Q: Design a car rental booking system

This is a System Design interview question from Moveworks for Software Engineer roles. View the full question and solution on PracHub.

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Question

System Design: Car Rental Booking System

Design an online car rental system (like Hertz/Avis) that allows users to search and book rental cars.

Core user flows

Search available cars by:
- pickup location
- pickup date/time and return date/time
- car class (economy/SUV/etc.) and optional filters (price, seats)
Quote pricing (base rate + fees + taxes).
Book a car.
Cancel / modify a reservation.

Requirements

Prevent double-booking of the same car for overlapping time ranges.
Handle high read traffic for search and spikes during promotions.
Provide good UX: quick search results and reliable booking confirmation.

Assumptions (you may choose reasonable defaults)

Fleet is organized by location; each car belongs to one location.
A reservation is a time interval $[start, end)$ with timezone-aware timestamps.

Deliverables

APIs (high level)
Data model
High-level architecture (services, storage, caching)
Concurrency/control approach (database locks / optimistic concurrency / distributed locks)
Scaling and reliability considerations