The system design practiceplatform for engineers.
Interactive problems, visual diagrams, and AI-powered feedback to help you build scalable systems.
Three steps to mastery.
Pick a problem
Filter real system-design questions asked at top tech companies by difficulty, company, and topic.
A video sharing platform with uploads, streaming, and recommendations.
A ride-sharing service with real-time matching and location tracking.
An end-to-end encrypted messaging platform at billions of messages a day.
A social platform with timeline feeds, tweets, and trending topics.
A service that maps long URLs to short codes and redirects at scale.
Cloud file storage and synchronization across multiple devices.
Throttle requests per client with a distributed token bucket.
Real-time team collaboration with channels, threads, and search.
A video sharing platform with uploads, streaming, and recommendations.
A ride-sharing service with real-time matching and location tracking.
An end-to-end encrypted messaging platform at billions of messages a day.
A social platform with timeline feeds, tweets, and trending topics.
A service that maps long URLs to short codes and redirects at scale.
Cloud file storage and synchronization across multiple devices.
Throttle requests per client with a distributed token bucket.
Real-time team collaboration with channels, threads, and search.
Design on the canvas
Drag real components like load balancers, caches, and databases, then connect them with clean orthogonal edges.
Get AI feedback
Submit for specific critique on availability, cost, and the write path, scored out of 100.
From zero to
interview-ready.
Learn the fundamentals
Master the building blocks: load balancing, caching, sharding, and message queues.
Solve easy problems
Warm up on URL shorteners, paste bins, and rate limiters. Learn tradeoffs without the complexity.
Tackle hard problems
Take on YouTube, Uber, and WhatsApp. Handle billions of users and real-time, global systems.
Ace your interview
Walk in confident. You have practiced real questions and acted on AI feedback every step.
Accepted
All test cases passed
Practice questions asked at
Stop guessing.
Start building.
Without LeetNode
With LeetNodeEvery design
earns its tier.
Submit a design and the evaluator scores it across four pillars, then stamps it Bronze through Platinum. Chase Platinum on every problem.
Overall
0/100
Interview-ready. Clear bottleneck analysis and well-argued tradeoffs end to end.
Questions? Answered.
Ready to level up?
Practice with real system design problems, get AI-powered feedback, and build scalable architectures visually.