Introduction

Just like LeetCode is essential for coding interview preparation, practicing system design problems is crucial for acing system design interviews. This guide covers the best platforms for practicing system design, curated problem lists, and effective preparation strategies.

Unlike coding problems which have clear solutions, system design problems are open-ended and require you to think through trade-offs, scalability, and architectural decisions. This post will help you find the right practice problems and platforms to master system design interviews.

Why Practice System Design Problems?

Key Benefits:

  1. Build Pattern Recognition: Recognize common patterns (caching, load balancing, sharding)
  2. Improve Communication: Practice explaining complex systems clearly
  3. Time Management: Learn to structure your approach within interview time limits
  4. Trade-off Analysis: Understand when to use different architectural patterns
  5. Scale Thinking: Develop intuition for handling millions/billions of users

Top System Design Practice Platforms

1. LeetCode System Design Section

URL: https://leetcode.com/explore/interview/card/system-design/

Features:

  • Curated system design problems
  • Discussion forums with solutions
  • Company-specific problem tags
  • Difficulty ratings

Best For:

  • Structured practice
  • Community solutions
  • Company-specific preparation

Popular Problems:

  • Design Twitter
  • Design Instagram
  • Design Facebook News Feed
  • Design a URL Shortener
  • Design a Web Crawler

2. Educative.io - Grokking the System Design Interview

URL: https://www.educative.io/courses/grokking-the-system-design-interview

Features:

  • Comprehensive course with 20+ problems
  • Step-by-step solutions
  • Visual diagrams
  • Real-world examples

Best For:

  • Learning fundamentals
  • Structured learning path
  • Visual learners

Course Structure:

  1. System Design Fundamentals
  2. Design Problems (20+ problems)
  3. Advanced Concepts
  4. Interview Tips

3. System Design Primer

URL: https://github.com/donnemartin/system-design-primer

Features:

  • Open-source GitHub repository
  • 100+ system design problems
  • Solutions and explanations
  • Interview tips

Best For:

  • Free comprehensive resource
  • Self-paced learning
  • Community contributions

Content:

  • System design basics
  • Scalability patterns
  • Design problems with solutions
  • Interview preparation guide

4. InterviewBit - System Design

URL: https://www.interviewbit.com/courses/system-design/

Features:

  • Curated problem list
  • Company-specific problems
  • Mock interviews
  • Solution explanations

Best For:

  • Indian tech companies
  • Structured practice
  • Mock interviews

5. Pramp - System Design Mock Interviews

URL: https://www.pramp.com/

Features:

  • Peer-to-peer mock interviews
  • Real-time practice
  • Feedback from peers
  • Free practice sessions

Best For:

  • Mock interview practice
  • Real-time feedback
  • Communication practice

6. Exponent - System Design Course

URL: https://www.tryexponent.com/courses/system-design

Features:

  • Video explanations
  • Practice problems
  • Company-specific content
  • Interview templates

Best For:

  • Video learners
  • Company-specific prep
  • Structured learning

7. AlgoExpert - System Design

URL: https://www.algoexpert.io/systems/product

Features:

  • Video explanations
  • Practice problems
  • Solution walkthroughs
  • Interview tips

Best For:

  • Visual learners
  • Step-by-step learning
  • Comprehensive coverage

Curated Problem Lists by Category

Beginner Problems (Start Here)

  1. Design a URL Shortener (TinyURL)
    • Learn: Hashing, database design, scaling
    • Difficulty: Easy
    • Time: 30-45 minutes
  2. Design a Pastebin
    • Learn: Storage, expiration, access control
    • Difficulty: Easy
    • Time: 30-45 minutes
  3. Design a Rate Limiter
    • Learn: Distributed systems, caching
    • Difficulty: Easy-Medium
    • Time: 45 minutes
  4. Design a Counter Service
    • Learn: Distributed counters, consistency
    • Difficulty: Easy-Medium
    • Time: 45 minutes

Intermediate Problems

  1. Design Twitter
    • Learn: Feed generation, social graph, real-time updates
    • Difficulty: Medium
    • Time: 45-60 minutes
  2. Design Instagram
    • Learn: Media storage, feed generation, CDN
    • Difficulty: Medium
    • Time: 45-60 minutes
  3. Design Facebook News Feed
    • Learn: Ranking algorithms, feed generation, caching
    • Difficulty: Medium-Hard
    • Time: 60 minutes
  4. Design a Chat System
    • Learn: Real-time messaging, WebSockets, message queues
    • Difficulty: Medium
    • Time: 45-60 minutes
  5. Design a Search Engine
    • Learn: Indexing, ranking, distributed search
    • Difficulty: Medium-Hard
    • Time: 60 minutes
  6. Design a Web Crawler
    • Learn: Queue management, politeness policies, distributed crawling
    • Difficulty: Medium-Hard
    • Time: 60 minutes

Advanced Problems

  1. Design Netflix
    • Learn: Video streaming, CDN, recommendation systems
    • Difficulty: Hard
    • Time: 60-90 minutes
  2. Design Uber
    • Learn: Real-time matching, geolocation, distributed systems
    • Difficulty: Hard
    • Time: 60-90 minutes
  3. Design a Distributed Cache
    • Learn: Consistent hashing, replication, eviction policies
    • Difficulty: Hard
    • Time: 60-90 minutes
  4. Design Google Drive
    • Learn: File storage, synchronization, versioning
    • Difficulty: Hard
    • Time: 60-90 minutes
  5. Design a Notification System
    • Learn: Message queues, push notifications, multi-channel delivery
    • Difficulty: Hard
    • Time: 60-90 minutes

Problem Categories by Topic

Storage & Databases

  • Design a Distributed Database
  • Design a Key-Value Store
  • Design a File Storage System
  • Design a Time-Series Database

Caching & Performance

  • Design a Distributed Cache
  • Design a CDN
  • Design a Rate Limiter
  • Design a Load Balancer

Messaging & Real-time

  • Design a Chat System
  • Design a Notification System
  • Design a Message Queue
  • Design a Real-time Analytics System

Search & Recommendation

  • Design a Search Engine
  • Design a Recommendation System
  • Design a News Feed
  • Design a Content Discovery System

Social & Media

  • Design Twitter
  • Design Instagram
  • Design Facebook
  • Design YouTube

E-commerce & Marketplace

  • Design Amazon
  • Design Uber
  • Design Airbnb
  • Design a Payment System

How to Practice Effectively

Step 1: Understand the Problem (5 minutes)

Questions to Ask:

  • What are the core features?
  • What’s the scale? (users, requests, data)
  • What are the performance requirements?
  • What’s out of scope?

Example:

  • Problem: Design Twitter
  • Questions: Do we need DMs? What about video? What’s the read:write ratio?

Step 2: Gather Requirements (5 minutes)

Document:

  • Functional requirements
  • Non-functional requirements (scale, latency, availability)
  • Constraints and assumptions

Step 3: High-Level Design (10 minutes)

Create:

  • System architecture diagram
  • Main components
  • Data flow
  • Technology choices

Step 4: Detailed Design (20 minutes)

Cover:

  • Database schema
  • API design
  • Caching strategy
  • Scalability considerations
  • Trade-offs

Step 5: Deep Dive (10 minutes)

Discuss:

  • Specific algorithms (ranking, sharding)
  • Failure scenarios
  • Monitoring and observability
  • Security considerations

Step 6: Wrap-up (5 minutes)

Summarize:

  • Key design decisions
  • Trade-offs made
  • Future improvements
  • Questions for interviewer

Practice Schedule

Week 1-2: Fundamentals

  • Day 1-2: Read system design basics
  • Day 3-4: Practice 2 beginner problems
  • Day 5-6: Practice 2 beginner problems
  • Day 7: Review and identify gaps

Week 3-4: Intermediate

  • Day 1-2: Practice 1 intermediate problem
  • Day 3-4: Practice 1 intermediate problem
  • Day 5-6: Practice 1 intermediate problem
  • Day 7: Review patterns learned

Week 5-6: Advanced

  • Day 1-2: Practice 1 advanced problem
  • Day 3-4: Practice 1 advanced problem
  • Day 5-6: Practice 1 advanced problem
  • Day 7: Mock interview practice

Week 7-8: Mock Interviews

  • Daily: 1 mock interview
  • Focus: Communication, time management
  • Review: Get feedback and improve

Common Patterns to Master

1. Load Balancing

  • Round-robin, least connections, IP hash
  • Layer 4 vs Layer 7 load balancing
  • Health checks and failover

2. Caching

  • Cache aside, write-through, write-behind
  • Cache invalidation strategies
  • Distributed caching (Redis, Memcached)

3. Database Sharding

  • Horizontal vs vertical sharding
  • Sharding strategies (range, hash, directory-based)
  • Consistent hashing

4. Replication

  • Master-slave replication
  • Master-master replication
  • Read replicas

5. Message Queues

  • Producer-consumer pattern
  • Pub-sub pattern
  • Dead letter queues

6. CDN

  • Edge caching
  • Content distribution
  • Cache invalidation

7. Rate Limiting

  • Token bucket
  • Leaky bucket
  • Fixed window
  • Sliding window

Company-Specific Preparation

Meta (Facebook)

Common Problems:

  • Design Facebook News Feed
  • Design Instagram
  • Design WhatsApp
  • Design Facebook Messenger

Focus Areas:

  • Social graphs
  • Feed generation
  • Real-time systems
  • Scalability at massive scale

Google

Common Problems:

  • Design Google Search
  • Design Google Drive
  • Design YouTube
  • Design Gmail

Focus Areas:

  • Search algorithms
  • Distributed systems
  • Big data processing
  • Scalability

Amazon

Common Problems:

  • Design Amazon
  • Design AWS S3
  • Design a Recommendation System
  • Design a Payment System

Focus Areas:

  • E-commerce systems
  • Cloud services
  • Distributed storage
  • Microservices

Netflix

Common Problems:

  • Design Netflix
  • Design a Video Streaming Service
  • Design a Recommendation System

Focus Areas:

  • Video streaming
  • CDN optimization
  • Recommendation algorithms
  • Content delivery

Uber

Common Problems:

  • Design Uber
  • Design a Ride-sharing System
  • Design a Real-time Matching System

Focus Areas:

  • Real-time systems
  • Geolocation
  • Matching algorithms
  • Distributed systems

Tips for Effective Practice

1. Time Yourself

  • Practice within interview time limits (45-60 minutes)
  • Learn to prioritize and make trade-offs

2. Draw Diagrams

  • Visualize your design
  • Use standard symbols and conventions
  • Practice drawing quickly

3. Explain Your Thinking

  • Practice explaining out loud
  • Record yourself and review
  • Get feedback from peers

4. Study Solutions

  • After attempting, study solutions
  • Understand different approaches
  • Learn from others’ designs

5. Focus on Trade-offs

  • Every design has trade-offs
  • Be able to explain why you chose one approach over another
  • Consider alternatives

6. Practice Communication

  • Clear and concise explanations
  • Structured approach
  • Handle interruptions gracefully

Resources for Learning

Books

  1. “Designing Data-Intensive Applications” by Martin Kleppmann
    • Deep dive into distributed systems
    • Database internals
    • Scalability patterns
  2. “System Design Interview” by Alex Xu
    • Interview-focused guide
    • Real examples
    • Step-by-step approach
  3. “High Scalability” Blog
    • Real-world architectures
    • Case studies
    • Scalability patterns

Online Courses

  1. Grokking the System Design Interview (Educative)
  2. System Design Primer (GitHub)
  3. System Design Interview (Exponent)

Blogs & Articles

  1. High Scalability: http://highscalability.com/
  2. AWS Architecture Center: https://aws.amazon.com/architecture/
  3. Google Cloud Architecture: https://cloud.google.com/architecture

Common Mistakes to Avoid

  1. Jumping to Solutions Too Quickly
    • Always gather requirements first
    • Ask clarifying questions
  2. Over-engineering
    • Start simple, then optimize
    • Don’t add unnecessary complexity
  3. Ignoring Scale
    • Always consider scale requirements
    • Think about bottlenecks
  4. Poor Communication
    • Practice explaining clearly
    • Use diagrams effectively
  5. Not Discussing Trade-offs
    • Always explain trade-offs
    • Consider alternatives
  6. Skipping Non-functional Requirements
    • Consider availability, latency, consistency
    • Discuss monitoring and observability

Mock Interview Practice

Where to Practice

  1. Pramp: Free peer-to-peer mock interviews
  2. Interviewing.io: Mock interviews with engineers
  3. Exponent: Mock interviews with feedback
  4. Friends/Colleagues: Practice with peers

What to Practice

  • Time management
  • Communication clarity
  • Handling interruptions
  • Asking clarifying questions
  • Drawing diagrams quickly

What Interviewers Look For

Practice & Preparation Skills

  1. Pattern Recognition
    • Recognizing common patterns
    • Applying patterns appropriately
    • Red Flags: No pattern recognition, wrong patterns, can’t apply
  2. Problem-Solving Approach
    • Structured thinking
    • Clear methodology
    • Red Flags: Random approach, no structure, disorganized
  3. Time Management
    • Appropriate depth for time
    • Prioritization
    • Red Flags: Poor time management, too detailed, too shallow

Communication Skills

  1. Clear Explanations
    • Explains thinking process
    • Uses diagrams effectively
    • Red Flags: Unclear, no diagrams, confusing
  2. Active Engagement
    • Asks clarifying questions
    • Responds to feedback
    • Red Flags: No questions, ignores feedback, defensive
  3. Trade-off Discussion
    • Discusses alternatives
    • Justifies decisions
    • Red Flags: No alternatives, no justification, can’t defend

System Design Skills

  1. Fundamental Knowledge
    • Core concepts understanding
    • Technology knowledge
    • Red Flags: Missing fundamentals, wrong knowledge, gaps
  2. Scale Thinking
    • Millions/billions of users
    • Appropriate optimizations
    • Red Flags: Small-scale thinking, no optimization, bottlenecks
  3. Practical Experience
    • Real-world considerations
    • Production awareness
    • Red Flags: Theoretical only, no practical knowledge, unrealistic

Problem-Solving Approach

  1. Requirements Clarification
    • Asks right questions
    • Understands scope
    • Red Flags: No questions, assumptions, wrong scope
  2. Iterative Refinement
    • Starts simple
    • Adds complexity as needed
    • Red Flags: Over-engineering, too complex, no iteration
  3. Edge Case Handling
    • Considers edge cases
    • Handles failures
    • Red Flags: Ignoring edge cases, no handling, incomplete

Meta-Specific Focus

  1. Systematic Practice
    • Regular practice
    • Pattern mastery
    • Key: Show systematic preparation
  2. Communication Excellence
    • Clear explanations
    • Active engagement
    • Key: Demonstrate communication skills

Summary

Key Takeaways:

  1. Practice Regularly: Consistent practice is essential
  2. Start Simple: Begin with beginner problems
  3. Study Solutions: Learn from others’ approaches
  4. Focus on Patterns: Master common patterns
  5. Practice Communication: Explain your thinking clearly
  6. Time Yourself: Practice within interview limits
  7. Mock Interviews: Get real-time feedback

Recommended Practice Path:

  1. Week 1-2: Learn fundamentals + beginner problems
  2. Week 3-4: Intermediate problems + pattern recognition
  3. Week 5-6: Advanced problems + deep dives
  4. Week 7-8: Mock interviews + refinement

Top Platforms:

  • LeetCode System Design
  • Educative Grokking
  • System Design Primer (GitHub)
  • Pramp (Mock interviews)

Remember: System design is about thinking through problems, making trade-offs, and communicating your design clearly. Practice regularly, study solutions, and focus on understanding the “why” behind design decisions.

Good luck with your system design interview preparation!