System Design Interview Questions and Answers
Experienced / Expert level questions & answers
Ques 1. Create a distributed cache system.
The system can use a consistent hashing algorithm to distribute keys across multiple cache nodes, and a mechanism to handle cache misses by fetching data from the main storage.
Example:
When a node receives a cache miss, it fetches the data from the main database and stores it in the cache for future requests.
Ques 2. Build a content delivery network (CDN).
The system includes edge servers strategically placed worldwide to cache and deliver static content, reducing latency and improving performance.
Example:
A user in Asia requests an image, and it's served from the nearest edge server instead of the origin server.
Ques 3. Design a scalable news feed system like Facebook's.
The system comprises a feed generation service, a storage system for user posts, and algorithms to rank and personalize the feed based on user interests.
Example:
User sees posts in their feed based on relevance and recency.
Ques 4. Build a fault-tolerant file storage system.
The system can replicate data across multiple servers, use erasure coding for data durability, and implement techniques like sharding for better performance.
Example:
Even if one server fails, the system ensures data availability and integrity.
Ques 5. Create a scalable video streaming service like Netflix.
The system includes a content delivery network, video encoding/transcoding servers, and a recommendation engine to provide a seamless streaming experience.
Example:
A user selects a movie, and the system streams it in high quality without buffering.
Ques 6. Design a distributed file system.
The system involves a master server for metadata, chunk servers for storing data, and a replication mechanism for fault tolerance.
Example:
A user uploads a large file, and it gets distributed and replicated across multiple servers for reliability.
Ques 7. Design a real-time stock trading system.
The system includes a trading engine, order matching algorithm, and a distributed database for storing real-time stock prices and transaction history.
Example:
A user places a stock order, and the system executes it in real-time based on market conditions.
Ques 8. Design a video conferencing system.
The system involves audio/video processing, real-time communication, and scalability to support multiple participants in a conference.
Example:
Multiple users join a video call, and the system ensures smooth communication with low latency.
Ques 9. Design a content moderation system for a user-generated platform.
The system uses machine learning models, user reports, and manual review to identify and filter inappropriate content.
Example:
A user posts content, and the system automatically detects and removes content violating community guidelines.
Ques 10. Design an e-commerce search engine.
The system involves indexing products, ranking algorithms, and handling user queries with efficient search and filtering capabilities.
Example:
A user searches for 'laptops,' and the system returns relevant products with sorting options.
Ques 11. Design a scalable IoT (Internet of Things) platform.
The system involves device connectivity, data processing, and storage for managing a large number of IoT devices and their data.
Example:
Sensors in smart home devices send data to the platform, and the system processes and stores the information for analysis.
Ques 12. Design a scalable message queue system.
The system involves message producers, queues, and consumers, with features like message persistence, load balancing, and fault tolerance.
Example:
Services in a microservices architecture communicate by sending messages through the queue.
Ques 13. Create a collaborative document editing system like Google Docs.
The system involves real-time collaboration, version control, and conflict resolution mechanisms to enable multiple users to edit a document simultaneously.
Example:
Several users edit a document together, and changes are reflected in real-time across all collaborating users.
Ques 14. Design an online multiplayer gaming system.
The system involves game servers, matchmaking algorithms, and real-time communication for a seamless multiplayer gaming experience.
Example:
Players from different locations connect to the game server and engage in a multiplayer game with low latency.
Ques 15. Design an event-driven architecture for a financial trading system.
The system uses events to trigger actions, ensuring real-time updates and responses to market changes in the financial trading domain.
Example:
A change in stock prices triggers automatic buy/sell orders in response to predefined trading algorithms.
Ques 16. Create a system for real-time analytics on a streaming data source.
The system involves data ingestion, processing, and analytics in real-time to provide insights on streaming data.
Example:
Sensor data from IoT devices is continuously analyzed to detect anomalies and trigger alerts in real-time.
Ques 17. Design a distributed task scheduling system.
The system manages the distribution and execution of tasks across multiple nodes, considering load balancing and fault tolerance.
Example:
A cluster of servers schedules and executes tasks in parallel to efficiently process a large workload.
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