100 System Design Interview Questions and Answers
CS Fundamentals · 100 questions, each with a full written answer — free, no sign-up.
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Basic
- What is a system design? Can you provide a brief overview?
- Can you differentiate between functional and non-functional requirements?
- What is the difference between high-level design and low-level design?
- What are some common components of a distributed system?
- What is the importance of scalability in system design? How can you achieve it?
- Can you explain the concept of horizontal and vertical scaling?
- What is caching and why is it important in system design?
- What is the CAP theorem? Can you provide a brief explanation of its three components?
- Can you explain the difference between a monolithic architecture and a microservices architecture?
- What is an API, and why is it important in system design?
- What is the role of a load balancer in a distributed system?
- Can you differentiate between stateless and stateful systems?
- What are the primary differences between synchronous and asynchronous communication in system design?
- What is data partitioning and why is it important in distributed systems?
- What are some common data storage options (e.g., SQL, NoSQL) and their differences?
- Can you provide a brief explanation of the client-server model?
- What is eventual consistency, and why is it important in distributed systems?
- What is a message queue, and what role does it play in system design?
- Can you briefly explain the concept of a content delivery network (CDN) and its importance in system design?
- What is fault tolerance, and why is it important in system design?
Intermediate
- Can you explain the concept of sharding in a database and its benefits?
- What are the different types of database indexes, and how do they help in optimizing queries?
- What are the four main components of a RESTful API?
- What are some common design patterns used in system design? Can you give a brief overview of a few?
- What are some strategies for designing systems that can handle high levels of traffic?
- How do you deal with data consistency in distributed systems?
- What is the role of a reverse proxy, and how does it differ from a load balancer?
- What is idempotency in the context of system design, and why is it important?
- Can you explain the concept of a service-oriented architecture (SOA)?
- How do you ensure data durability in a distributed system?
- What are some common techniques for optimizing database performance?
- How do you handle bottlenecks in system design?
- What is a publish-subscribe pattern, and how does it differ from a request-response pattern?
- Can you explain the benefits and drawbacks of using a NoSQL database over a traditional SQL database?
- What is a session in the context of system design, and how can you manage session state?
- What are some key considerations when designing a system for high availability?
- Can you explain the concept of data replication in distributed systems and its importance?
- What is a circuit breaker pattern, and how does it help in improving the resilience of a system?
- What are the key factors to consider when choosing between synchronous and asynchronous communication in a system?
- Can you discuss the importance of monitoring and logging in a well-designed system?
Advanced
- Can you discuss the concept of backpressure in system design and how it can be managed?
- How do you handle schema changes and migrations in a distributed database system?
- What are some strategies for implementing rate limiting in a system?
- Can you discuss the importance of versioning in APIs, and what are some best practices for managing API versions?
- How do you approach designing a system for handling time-series data?
- How do you deal with eventual consistency and conflicts in a distributed system that uses optimistic concurrency control?
- Can you discuss different consistency models in distributed systems, such as strong consistency, weak consistency, and causal consistency?
- What are some strategies for implementing efficient search functionality in a large-scale system?
- How do you design a system that can handle real-time data processing and analytics?
- Can you explain the concept of quorum in the context of distributed systems, and why it’s important?
- How do you ensure data security and privacy in a distributed system?
- What is the role of a consensus algorithm in a distributed system, and can you discuss some common examples?
- Can you discuss strategies for implementing graceful degradation in a system?
- How do you design an efficient notification system that can handle a large number of users?
- What are some challenges associated with designing systems that need to handle geographically distributed data?
- Can you discuss the trade-offs between push and pull models in data processing and communication?
- How do you design a system for efficiently handling large file uploads and downloads?
- What are some strategies for handling hotspots in distributed systems, such as hot partitions or hot keys?
- Can you discuss techniques for optimizing system performance through caching, such as cache eviction policies and cache hierarchy?
- How do you handle data retention and archiving in a system that generates a large volume of data over time?
Expert
- Can you discuss the challenges and best practices in designing a globally distributed, multi-region system?
- How do you approach designing a system with support for multi-tenancy and data isolation?
- What are some strategies for handling data deduplication and compression in large-scale systems?
- How do you design a system with support for long-running transactions and distributed transactions?
- Can you discuss the concept of a "shared nothing" architecture and its advantages and disadvantages?
- How do you ensure resilience and fault-tolerance in a system with many dependencies on external services?
- Can you discuss strategies for implementing end-to-end encryption in a distributed system?
- How do you design a system to handle large-scale, real-time stream processing and complex event processing?
- What are some strategies for designing a system with support for both online and offline processing?
- How do you approach designing a system that requires complex data synchronization and conflict resolution?
- What are some best practices for optimizing the performance of distributed databases and storage systems?
- How do you design a system with support for complex access control and authentication mechanisms?
- Can you discuss the challenges and best practices for implementing A/B testing and feature flagging in a large-scale system?
- How do you approach designing a system with support for real-time collaboration and conflict resolution?
- Can you discuss strategies for implementing a distributed, fault-tolerant, and scalable messaging system?
- What are some best practices for ensuring observability and monitoring in large-scale, distributed systems?
- How do you design a system with support for dynamic scaling, including auto-scaling and scale-in mechanisms?
- Can you discuss the challenges and best practices for implementing machine learning models in a distributed system?
- How do you approach capacity planning and performance testing for large-scale, distributed systems?
- What are some best practices for designing and implementing a robust disaster recovery strategy in a distributed system?
Guru
- Can you discuss advanced strategies for achieving linearizability and serializability in distributed databases?
- How do you design a distributed system with support for advanced data processing, such as graph processing or semantic analysis?
- Can you discuss the challenges and best practices for implementing geo-replication and data locality in global-scale systems?
- What are some advanced techniques for optimizing query performance in distributed databases, such as materialized views or query rewriting?
- How do you design a system with support for advanced consistency guarantees, such as snapshot isolation or external consistency?
- Can you discuss the challenges and best practices for implementing advanced data management techniques, such as multi-master replication or distributed transactions?
- What are some advanced strategies for achieving fault-tolerance and self-healing in large-scale, distributed systems?
- How do you approach designing a distributed system with support for advanced analytics, such as machine learning or data mining?
- Can you discuss the challenges and best practices for implementing distributed machine learning and model serving in large-scale systems?
- What are some advanced techniques for optimizing the performance and efficiency of data storage and retrieval, such as data compression or tiered storage?
- How do you design a distributed system with support for advanced security and privacy requirements, such as zero-knowledge proofs or secure multi-party computation?
- Can you discuss the challenges and best practices for implementing advanced event-driven architectures and stream processing in large-scale systems?
- What are some advanced strategies for handling data versioning and schema evolution in distributed systems?
- How do you approach designing a distributed system with support for advanced data provenance and lineage tracking?
- Can you discuss the challenges and best practices for implementing complex data synchronization techniques, such as operational transformation or conflict-free replicated data types (CRDTs)?
- What are some advanced techniques for optimizing network communication and data transfer in large-scale, distributed systems?
- How do you design a system with support for advanced resource management and allocation, such as workload prioritization or quality of service (QoS) guarantees?
- Can you discuss the challenges and best practices for implementing advanced monitoring and observability features, such as distributed tracing or anomaly detection?
- What are some advanced strategies for managing system complexity and technical debt in large-scale, distributed systems?
- Can you discuss the challenges and best practices for implementing advanced distributed consensus algorithms and protocols, such as Byzantine fault tolerance or blockchain-based consensus?
📕 Buy this interview preparation book: 100 System Design questions & answers — PDF + EPUB for $5
Reading is step one. Saying it out loud is the interview.
Our AI interviewer calls your phone and runs a realistic System Design interview — then scores it.
📞 Practice System Design — free 15 min