System requirements

Functional:

• Vehicle identification via license plate recognition.
• User account verification for regular customers.
• Real-time tracking of vehicle locations and durations.
• Efficient vehicle retrieval for quick exits.
• User registration and vehicle association.
• Real-time availability of parking spots.
• Spot allocation based on vehicle size and user preferences.
• Payment processing integration.

Non-Functional:

• Scalability for at least 1,000 parking spots.
• 99.9% uptime for high availability.
• Redundancy and failover for reliability.

Capacity estimation

Estimate the scale of the system you are going to design...

API design

User API:

• Endpoint: /users
• Method: POST (for creation), GET (for retrieval)
• Data: User details for registration, credentials for login.
• Response: User ID on registration, authentication token on login.

Vehicle API:

• Endpoint: /vehicles
• Method: POST (for registration), GET (for retrieval)
• Data: Vehicle details, user ID.
• Response: Vehicle ID, tier information.

Parking API:

• Endpoint: /parking
• Method: GET (for spot availability), POST (for allocation)
• Data: Vehicle ID, user preferences.
• Response: Spot number, location details.

Payment API:

• Endpoint: /payments
• Method: POST (for processing)
• Data: Payment details, user ID.
• Response: Transaction status, receipt.

Notification API:

• Endpoint: /notifications
• Method: POST (for sending)
• Data: User ID, message content.
• Response: Delivery status.

Database design

• SQL Database:
• Tables for Users, Vehicles, Transactions, and ParkingSpots.
• Normalization to reduce redundancy.
• Indexes on vehicle_id, user_id, and spot_id for efficient queries.
• Partitioning by date to enhance performance and manage data growth.
• NoSQL Database:
• Document-based storage for analytical data.
• Denormalization for optimized reads.
• Sharding by vehicle_type or user_type for load distribution.

High-level design

Microservices:

• User Service:
• User Registration: Implements an endpoint to accept user details and create new accounts. It stores user information securely and provides unique identifiers for each user.
• Login and Authentication: Offers secure authentication mechanisms, such as OAuth 2.0, and generates tokens for session management.
• Vehicle Service:
• Vehicle Data Management: Registers vehicles to user accounts and stores details like make, model, and tier preferences. It also assigns a unique vehicle ID for tracking within the system.
• Parking Service:
• Spot Allocation: Uses algorithms to determine the best available spot based on the vehicle’s size and user preferences. It updates the parking spot status in real-time.
• Spot Availability: Provides real-time data on available spots, helping users find the nearest parking plot efficiently.
• Payment Service:
• Payment Processing: Handles transactions by interfacing with payment gateways. It ensures secure processing of payments and maintains transaction records.
• Notification Service:
• Alerts and Notifications: Sends notifications to users regarding parking status, payments, and other relevant information. It can also alert staff about parking lot incidents or full capacity.

Request flows

Explain how the request flows from end to end in your high level design. Also you could draw a sequence diagram using the diagramming tool to enhance your explanation...

Detailed component design

Dig deeper into 2-3 components and explain in detail how they work. For example, how well does each component scale? Any relevant algorithm or data structure you like to use for a component? Also you could draw a diagram using the diagramming tool to enhance your design...

Trade offs/Tech choices

Explain any trade offs you have made and why you made certain tech choices...

Failure scenarios/bottlenecks

Future improvements

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