Best Scenario Based Interview Questions on High Level System Design[Answered]

Introduction:

Welcome to our new post on Best Scenario Based Interview Questions on High Level System Design[answered].

In system design interviews, candidates are often presented with scenario-based questions to evaluate their ability to architect complex systems, considering aspects like scalability, reliability, performance, and security. These questions aim to assess the candidate’s understanding of various components, their interactions, and best practices in software engineering. In this document, we explore five common high-level system design scenarios: a URL shortener service, an e-commerce system, a real-time chat application, a ride-sharing service, and a cloud storage service. Each scenario includes a detailed description of the key components, their interactions, and important considerations for building robust and efficient systems.

Best Scenario Based Interview Questions on High Level System Design[Answered]

Scenario-Based Interview Questions on High-Level System Design

1. Design a URL Shortener Service

Question:
Design a URL shortener like bit.ly. Discuss the key components and their interactions.

Components:

• User Interface: For inputting long URLs and displaying short URLs.
• API Gateway: To handle incoming API requests.
• Database: To store the mapping between long and short URLs.
• Key Generation Service: To generate unique short keys.
• Redirection Service: To redirect short URLs to their corresponding long URLs.

Flow:

1. User inputs a long URL.
2. The system generates a unique short key using the Key Generation Service.
3. Store the mapping in the database.
4. Provide the short URL to the user.
5. When the short URL is accessed, the Redirection Service fetches the long URL from the database and redirects the user.

• Considerations:
• Scalability: Use a distributed database (e.g., Cassandra) to handle a large number of mappings.
• Reliability: Implement replication and backups for the database.
• Performance: Use caching (e.g., Redis) for frequently accessed URLs.

2. Design an E-Commerce System

Question:
Design an e-commerce system that handles user authentication, product catalog, order management, and payment processing.

• Components:
• User Service: For user registration, authentication, and profile management.
• Product Catalog Service: For managing product details, categories, and inventory.
• Order Service: For handling orders, order status, and history.
• Payment Service: For processing payments and managing transactions.
• Notification Service: For sending order confirmations and shipping updates.
• Database: For storing user data, product details, order information, and payment records.

Flow :

1. User registers and logs in using the User Service.
2. User browses the product catalog and adds items to the cart.
3. User places an order, which is handled by the Order Service.
4. The Payment Service processes the payment.
5. Order status is updated, and notifications are sent via the Notification Service.

• Considerations:
• Scalability: Microservices architecture allows scaling individual components.
• Security: Implement SSL for secure communication, encrypt sensitive data, and follow PCI-DSS for payment processing.
• Reliability: Use a distributed database (e.g., MongoDB) with replication and backups.
• Performance: Use caching for product details and order histories.

3. Design a Real-Time Chat Application

Question:
Design a real-time chat application like WhatsApp or Slack.

• Components:
• User Service: For user registration, authentication, and profile management.
• Chat Service: For handling real-time messaging.
• Notification Service: For sending push notifications.
• Database: For storing user data, message history, and chat rooms.
• WebSocket Server: For real-time communication between clients and the server.

Flow :

1. User registers and logs in using the User Service.
2. User joins a chat room or starts a new chat.
3. Messages are sent and received in real-time via the WebSocket Server.
4. Messages are stored in the database for history.
5. Notifications are sent for new messages when the user is offline.

• Considerations:
• Scalability: Use a distributed messaging system (e.g., Apache Kafka) for handling high message throughput.
• Reliability: Implement message delivery guarantees (e.g., at least once delivery).
• Performance: Optimize WebSocket connections and use load balancers to distribute traffic.
• Security: Encrypt messages in transit and at rest, and implement end-to-end encryption for private chats.

4. Design a Ride-Sharing Service

Question:
Design a ride-sharing service like Uber or Lyft.

• Components:
• User Service: For passenger and driver registration, authentication, and profile management.
• Ride Matching Service: For matching passengers with drivers.
• Trip Management Service: For handling trip details, status, and history.
• Payment Service: For processing ride payments and managing transactions.
• Notification Service: For sending ride confirmations and updates.
• Location Service: For real-time tracking of driver and passenger locations.
• Database: For storing user data, trip details, payment records, and location history.

Flow:

1. User registers and logs in using the User Service.
2. Passenger requests a ride using the Ride Matching Service.
3. Ride Matching Service finds a nearby driver and assigns the ride.
4. Trip details are managed by the Trip Management Service.
5. Payment is processed by the Payment Service at the end of the trip.
6. Notifications are sent for ride updates and confirmations.
7. Real-time tracking is handled by the Location Service.

• Considerations:
• Scalability: Microservices architecture allows scaling individual components.
• Reliability: Implement redundancy and failover mechanisms for critical services.
• Performance: Optimize real-time location tracking and matching algorithms.
• Security: Ensure secure communication and data storage, and implement fraud detection mechanisms.

5. Design a Cloud Storage Service

Question:
Design a cloud storage service like Dropbox or Google Drive.

• Components:
• User Service: For user registration, authentication, and profile management.
• File Storage Service: For storing and retrieving files.
• Metadata Service: For managing file metadata, versioning, and access controls.
• Synchronization Service: For syncing files across devices.
• Notification Service: For sending updates on file changes.
• Database: For storing user data, file metadata, and synchronization states.

Flow:

1. User registers and logs in using the User Service.
2. User uploads files, which are handled by the File Storage Service.
3. File metadata is managed by the Metadata Service.
4. Files are synchronized across devices by the Synchronization Service.
5. Notifications are sent for file updates via the Notification Service.

• Considerations:
• Scalability: Use a distributed file system (e.g., HDFS) to handle large volumes of data.
• Reliability: Implement replication and backups for data.
• Performance: Optimize file upload/download speeds and synchronization mechanisms.
• Security: Encrypt files in transit and at rest, and implement access controls.

Reference:

High Level System Design

Best Scenario Based Interview Questions On Low Level System Design [Answered]

Conclusion:

Conclusion

In designing high-level systems, the key to success lies in understanding the core requirements, anticipating potential challenges, and crafting an architecture that balances scalability, reliability, and performance.

1. Scalability ensures that the system can handle increasing loads and grow as needed without sacrificing performance. Strategies like horizontal scaling, database sharding, and leveraging caches are essential for managing high traffic and large volumes of data effectively.
2. Reliability is crucial for maintaining service availability and consistency. Implementing redundancy, replication, and failover mechanisms helps protect against failures and ensures that the system remains operational under various conditions.
3. Performance and low latency are achieved through optimized data handling, efficient communication protocols, and strategic use of edge servers and CDNs to enhance user experience and responsiveness.
4. Security safeguards data integrity and user privacy, involving encryption, robust authentication mechanisms, and adherence to industry standards and regulations.

By approaching system design with these principles in mind, you can create robust, scalable, and efficient solutions that meet user needs and adapt to evolving demands. Each scenario may present unique challenges, but a well-thought-out architectural strategy ensures that the system can effectively manage complexity and deliver a high-quality user experience.