System Design Mock Interview
Practice designing scalable systems with an AI interviewer. Get architecture questions tailored to your seniority with feedback on your trade-off decisions, component choices, and scalability reasoning.
Start System Design Practice →Topics Covered in System Design Interviews
Scalability & Load Handling
Horizontal vs. vertical scaling, load balancers, auto-scaling groups, CDNs, and capacity estimation for millions of users.
Database Design
SQL vs. NoSQL trade-offs, sharding strategies, replication, indexing, denormalization, and choosing the right database for the workload.
Caching Strategies
Cache invalidation, write-through vs. write-back, Redis/Memcached use cases, and cache consistency in distributed systems.
Distributed Systems
CAP theorem, eventual consistency, message queues, event-driven architecture, and handling network partitions.
API Design
REST vs. GraphQL, rate limiting, pagination, versioning, authentication, and backward compatibility.
How to Approach System Design Questions
- Clarify requirements — Ask about scale (users, requests/sec), features in scope, and constraints.
- Define the high-level architecture — Draw the major components: clients, load balancer, application servers, databases, caches.
- Deep-dive into components — Pick 2–3 critical areas and discuss detailed design decisions.
- Discuss trade-offs — Every design has compromises. Acknowledge them and explain why you chose one approach over another.
- Address bottlenecks — Identify single points of failure and explain how to mitigate them.
Example System Design Questions
- Design a URL shortener (like bit.ly) that handles 100M links/day
- Design a real-time chat system for 10M concurrent users
- Design a news feed algorithm for a social network
- Design a ride-sharing service matching drivers and riders
- Design a video streaming platform's content delivery
- Design a distributed key-value store with strong consistency
JobChef generates questions at your experience level and follows up based on your answers, just like a real interviewer.
Practice System Design Now
Free tokens on signup. AI adapts to your seniority level.
Launch System Design Interview →