Ace Your System Design Skills
Practice system design with an AI interviewer: draw diagrams, get AI hints, and receive scored feedback across 6 categories.
- 6
- scoring categories
- 2
- AI interviewer + mentor
- โ
- attempts, all scored
Strong structure, but trade-offs and failure handling went unjustified.
See exactly where you stood
ChatGPT can't tell you that capacity estimation is your weak spot. We can: per interview, and across every attempt.
- High-Level Design. Decomposed the system into logical services and traced data flow end-to-end.
- Requirements. Clarified functional and non-functional constraints before designing.
- Trade-offs. Chose solutions without weighing alternatives, so the decisions went unjustified.
- Failure Modes. No cascading failures or partial degradation; circuit breakers never considered.
Your weak spot shows up over time
Every session is recorded and scored. Your profile surfaces the category that keeps holding you back, and how it moves attempt over attempt.
* Sample profile data
Three ways to keep the bar high
Problems for AI Engineers
Design ML pipelines, vector search systems, LLM inference infrastructure, and RAG architectures: problems tailored for engineers building AI products.
Quick Drills
Short, focused sessions on a single topic: caching, database sharding, hashing, and more. Perfect for warming up or drilling a specific weak spot without committing to a full interview.
Hard Mode
Crank up the pressure: the interviewer probes every corner case and won't let you move on until all nuances are covered. Closest thing to a real FAANG interview.
A full interview loop, not a set of drills
Curated Design Problems
A growing set of system design problems covering a wide range, from URL shorteners to distributed caches.
AI Interviewer
Practice with Alex, an AI Staff Engineer who asks probing questions and guides you through the design.
Private AI Mentor
Meet Sam, your private AI mentor. Ask anything during the interview (clarify concepts, explore trade-offs, or get unstuck) without affecting your score.
Scored Feedback
Get a detailed verdict with scores across 6 categories and actionable feedback to improve.
Track Your Progress
Your profile shows completion stats, scores across all attempts, and a history of every session, so you always know where you stand.
Curated by Real Interviews
Problems are tagged by company, interview frequency, and topic category, helping you focus on what matters for your target role.
What people say
The verdict caught that I never justified my sharding choice. My next loop, the interviewer asked exactly that, and I had the answer.
Hard Mode is brutal in the best way. It kept probing failure modes until I actually thought about circuit breakers.
Seeing capacity estimation flagged as my weak category across five sessions was the kick I needed. Up 20 points now.
Frequently asked questions
- What is LeetDesign?
- LeetDesign is an AI-powered platform for practicing system design interviews. You work with an AI interviewer, get hints from a private AI mentor, draw on an interactive whiteboard, and receive scored feedback across 6 categories: requirements, capacity planning, high-level design, deep dive, trade-offs, and failure modes.
- What is a system design interview?
- A system design interview asks you to design a scalable, real-world system โ such as a URL shortener, a distributed cache, or a social news feed โ while explaining your decisions to the interviewer. It evaluates your knowledge of distributed systems, databases, APIs, and architectural trade-offs.
- How do I prepare for a system design interview?
- Effective preparation means practicing realistic end-to-end problems, learning to estimate capacity, studying patterns like caching, load balancing, and database sharding, and articulating trade-offs clearly. LeetDesign lets you practice with an AI interviewer that probes your design the same way a real Staff Engineer would.
- What does LeetDesign evaluate in an interview?
- Your session is scored across 6 categories: Requirements Clarification, Capacity Planning, High-Level Design, Deep Dive, Trade-offs Analysis, and Failure Modes. You receive a per-category score and an overall hire / borderline / no-hire recommendation.
- Is LeetDesign free?
- All problems are free to practice โ no credit card required. The only paid feature is certification: a proctored, time-limited interview in hard mode with no hints or mentor. If you pass, you receive a public verifiable certificate (Gold/Silver/Bronze).
- What kinds of system design problems are available?
- LeetDesign covers a wide range: URL shorteners, distributed caches, social feeds, notification systems, ML pipelines, vector search engines, LLM inference infrastructure, and RAG architectures. Problems are tagged by difficulty, interview frequency, and topic.
Sit a real system design interview tonight
No signup wall, no card. Find out the score you'd actually get, and what to fix before the real loop.