Sign in to track progress, unlock prep layers, and browse your pipeline.Sign in
System Design: Car Rental Platform
Objective
Design a comprehensive car rental platform. Your design should include:
- Core Entities and Relationships: Identify and define the essential entities such as customer, vehicle, vehicle type, branch/location, inventory unit, reservation, rental/contract, payment, pricing rule, promotion, insurance, availability/hold, staff, and damage report. Illustrate their relationships.
- Relational Database Schema: Propose a relational database schema, including primary and foreign keys, unique constraints, and critical indexes. Pay special attention to indexes required for efficient availability lookups by location and date/time windows.
- End-to-End Workflows and Consistency: Detail the workflows and consistency requirements for the following key operations:
- Availability Search: Searching for available vehicles by location and a specified date/time window.
- Reservation Management: Creating, modifying, and canceling reservations, ensuring transactional holds are used to prevent double-booking.
- Rental Lifecycle: Handling vehicle pick-up (including vehicle assignment, contract generation, and inspection) and return (recording mileage, fuel levels, damages, and calculating late fees).
- Pricing Engine: Calculating rental costs based on base rates, mileage, insurance add-ons, taxes, and applying promotions.
- Payment Processing: Managing payment authorization, capture, and refunds.
- Representative REST Endpoints: Define 3–5 REST API endpoints with their request and response fields. Examples include
POST /search,POST /reservations,PATCH /reservations/{id}, andPOST /rentals/{id}/return. - Cross-Cutting Concerns: Address critical cross-cutting concerns such as idempotency, pagination, authentication/authorization, concurrency control (e.g., using row locks or optimistic versioning), and scaling strategies (e.g., read replicas, partitioning by branch/region, caching for hot availability queries).
Constraints and Assumptions
- The platform must use a relational database (e.g., PostgreSQL).
- All time-related data should be stored in UTC, with branch locations having associated local timezone metadata.
- Vehicle availability is primarily managed at the vehicle type level for a specific branch. The assignment of a specific physical vehicle unit occurs only at the time of pick-up.
- The system must prevent overlaps and double-booking through the use of transactional holds and database constraints.
AI interview prep
Core dilemma
Managing complex, time-sensitive inventory (vehicle types at branches) with high consistency requirements for reservations and financial transactions, under varying load, while ensuring data integrity and preventing double-booking across multiple concurrent operations.
Mid-level signals3
Senior signals3
Red flags3
3 tradeoffs and 3 stress tests locked
Interview prep
Unlock the interviewer X-Ray rubric, tradeoff matrix, stress tests, clarifying questions, and key concepts.
System Design: Car Rental Platform
Objective
Design a comprehensive car rental platform. Your design should include:
- Core Entities and Relationships: Identify and define the essential entities such as customer, vehicle, vehicle type, branch/location, inventory unit, reservation, rental/contract, payment, pricing rule, promotion, insurance, availability/hold, staff, and damage report. Illustrate their relationships.
- Relational Database Schema: Propose a relational database schema, including primary and foreign keys, unique constraints, and critical indexes. Pay special attention to indexes required for efficient availability lookups by location and date/time windows.
- End-to-End Workflows and Consistency: Detail the workflows and consistency requirements for the following key operations:
- Availability Search: Searching for available vehicles by location and a specified date/time window.
- Reservation Management: Creating, modifying, and canceling reservations, ensuring transactional holds are used to prevent double-booking.
- Rental Lifecycle: Handling vehicle pick-up (including vehicle assignment, contract generation, and inspection) and return (recording mileage, fuel levels, damages, and calculating late fees).
- Pricing Engine: Calculating rental costs based on base rates, mileage, insurance add-ons, taxes, and applying promotions.
- Payment Processing: Managing payment authorization, capture, and refunds.
- Representative REST Endpoints: Define 3–5 REST API endpoints with their request and response fields. Examples include
POST /search,POST /reservations,PATCH /reservations/{id}, andPOST /rentals/{id}/return. - Cross-Cutting Concerns: Address critical cross-cutting concerns such as idempotency, pagination, authentication/authorization, concurrency control (e.g., using row locks or optimistic versioning), and scaling strategies (e.g., read replicas, partitioning by branch/region, caching for hot availability queries).
Constraints and Assumptions
- The platform must use a relational database (e.g., PostgreSQL).
- All time-related data should be stored in UTC, with branch locations having associated local timezone metadata.
- Vehicle availability is primarily managed at the vehicle type level for a specific branch. The assignment of a specific physical vehicle unit occurs only at the time of pick-up.
- The system must prevent overlaps and double-booking through the use of transactional holds and database constraints.