AlgoMaster Logo

How to Take this Course

6 min readUpdated December 24, 2025
Listen to this chapter
Unlock Audio

This course contains over 50 system design problems, 20 technology deep dives, and dozens of concepts and patterns. You do not need to cover everything to ace your interview.

This chapter will help you navigate the course efficiently based on your experience level and available preparation time.

Understanding the Course Structure

The course is organized into two main parts:

Part 1: Foundations

  • Introduction (understanding interviews)
  • Must-Know Topics (essential concepts, technologies, data structures, tradeoffs)
  • Concept Deep Dives (networking, caching, distributed systems, API design, database design)
  • Technology Deep Dives (20 technologies from PostgreSQL to Kubernetes)
  • Interview Patterns (19 recurring patterns like fanout, hot keys, real-time updates)
  • Interview Tips (frameworks, estimation, diagramming)

Part 2: Interview Problems

  • 50+ problems organized into 12 categories (real-time communication, social media, location-based services, distributed infrastructure, etc.)

The 80/20 Rule for System Design

Here’s the reality: you can answer ~80% of system design interview questions well by mastering ~20% of the material.

That high-leverage 20% is mostly:

  • Core building blocks that appear everywhere (caching, databases, load balancing, messaging/queues, storage, indexing)
  • Core tradeoffs (consistency vs availability, latency vs throughput, cost vs performance, simplicity vs scalability)
  • Recurring patterns that keep repeating (fanout, real-time updates, high read traffic, high write traffic, hot keys)

Once you understand these fundamentals deeply, you can tackle unfamiliar problems by combining what you know.

Learning Path by Experience Level

Junior Engineers (0-2 Years)

Your interviews will focus on fundamentals, not advanced distributed systems.

Start here:

  1. Complete the entire Introduction section
  2. Study all Must-Know Topics thoroughly
  3. Read the Interview Tips section (especially Answering Framework and Clarifying Requirements)

Concept Deep Dives to prioritize:

  • Caching (appears in 90% of problems)
  • Database Design (you will need this for every problem)
  • API Design (demonstrates communication skills)

Technology Deep Dives to focus on:

  • PostgreSQL or MySQL (pick one relational database)
  • Redis (caching is fundamental)
  • Kafka (basic message queue understanding)

Skip Cassandra, DynamoDB, Flink, Spark, and Zookeeper for now. These are advanced topics.

Interview Problems to practice:

  1. Design URL Shortener (simplest problem, teaches core concepts)
  2. Design WhatsApp (real-time communication fundamentals)
  3. Design Instagram (social media basics)
  4. Design Spotify (media delivery basics)
  5. Design Yelp (location-based services basics)
  6. Design Search Autocomplete (search fundamentals)

These 6 problems cover the major categories without overwhelming complexity.

Interview Patterns to study:

  • Realtime Updates
  • High Read Traffic
  • High Write Traffic
  • Fanout

These four patterns cover the majority of scenarios you will encounter.

Mid-Level Engineers (2-5 Years)

You are expected to go deeper into specific components and discuss tradeoffs.

Start here:

  1. Review Introduction (should be familiar)
  2. Study all Must-Know Topics
  3. Complete all Concept Deep Dives
  4. Read all Interview Tips

Technology Deep Dives to prioritize:

  • One relational database (PostgreSQL or MySQL)
  • One NoSQL database (MongoDB, Cassandra, or DynamoDB)
  • Redis and Memcached (understand the differences)
  • Elasticsearch (search is common in interviews)
  • Kafka (message queues are essential)
  • S3 (object storage comes up often)
  • Nginx (load balancing basics)

Interview Problems to practice:

Start with the free problems in each category, then expand:

  1. Core problems (do these first):
    • Design URL Shortener
    • Design WhatsApp
    • Design Instagram
    • Design Spotify
    • Design Yelp
    • Design Search Autocomplete
  2. Intermediate problems (add these next):
    • Design Unique ID Generator
    • Design Pastebin
    • Design Slack
    • Design TikTok
    • Design Netflix
    • Design Uber
    • Design Google Search
    • Design Amazon
    • Design Rate Limiter
    • Design Notification Service
  3. Infrastructure problems (important for mid-level):
    • Design Distributed Cache
    • Design Key-Value Store
    • Design Messaging Queue

Interview Patterns to study:All 19 patterns, with extra focus on:

  • Hot Keys
  • Traffic Spikes
  • Handling Large Files
  • Deduplicating Data

Senior Engineers (5+ Years)

You are expected to drive the conversation, make architectural decisions confidently, and dive deep into any component.

Your approach:

  1. Skim Introduction (validate your understanding)
  2. Review Must-Know Topics for gaps
  3. Complete all Concept Deep Dives
  4. Study all Technology Deep Dives (you should know when to use each)
  5. Master all Interview Patterns
  6. Practice a wide variety of problems

Technology Deep Dives priority:

Study all 20 technologies. At your level, interviewers will expect you to discuss specific technology choices with depth.

Pay special attention to:

  • Cassandra vs DynamoDB (distributed database tradeoffs)
  • Kafka vs RabbitMQ vs SQS (message queue selection)
  • Flink vs Spark (stream vs batch processing)
  • Zookeeper (coordination in distributed systems)
  • Kubernetes (container orchestration is expected knowledge)
  • Prometheus (observability matters)

Interview Problems to practice:

Focus on complex infrastructure and specialized systems:

  1. Distributed Infrastructure (highest priority):
    • Design Load Balancer
    • Design API Gateway
    • Design Key-Value Store
    • Design Distributed Cache
    • Design CDN
    • Design Object Storage
    • Design Messaging Queue
    • Design Locking Service
  2. Complex real-world systems:
    • Design Google Docs (collaborative editing is challenging)
    • Design Stock Exchange (low latency, consistency)
    • Design Zoom (real-time media at scale)
    • Design Google Maps (location + routing at scale)
    • Design CI/CD Pipeline (dev tooling)
    • Design Monitoring and Alerting System
  3. Counting and Ranking (often overlooked):
    • Design Distributed Counter
    • Design Likes Counting System
    • Design Top K
    • Design Real Time Leaderboard

Interview Patterns to master:All 19 patterns, with particular depth in:

  • Multi-Tenancy
  • Sandboxing
  • Media Streaming
  • Fairness
  • Removing Single Point of Failures
  • Distributed Tracing

Study Plans by Available Time

1 Week (Crash Course)

You have very limited time. Focus on maximum impact.

Days 1-2: Foundations

  • Read all Introduction chapters
  • Study Must-Know Topics (Concepts and Technologies only)
  • Read Answering Framework and Estimation Cheatsheet

Days 3-4: Core Concepts

  • Caching Deep Dive
  • Database Design Deep Dive
  • Study 3 patterns: Realtime Updates, High Read Traffic, Fanout

Days 5-7: Problem PracticePractice these 5 problems (one per day, with review):

  1. Design URL Shortener
  2. Design WhatsApp
  3. Design Instagram
  4. Design Yelp
  5. Design Search Autocomplete

What to skip: Technology Deep Dives (except skimming Redis), advanced patterns, complex problems.

2 Weeks (Focused Preparation)

Week 1: Build the Foundation

Days 1-2:

  • All Introduction chapters
  • All Must-Know Topics

Days 3-5:

  • All Concept Deep Dives
  • All Interview Tips

Days 6-7:

  • Technology Deep Dives: PostgreSQL, Redis, Kafka, S3

Week 2: Problem Practice

Practice 10 problems, two per day:

  1. Design URL Shortener + Design Unique ID Generator
  2. Design WhatsApp + Design Instagram
  3. Design Spotify + Design Netflix
  4. Design Yelp + Design Uber
  5. Design Search Autocomplete + Design Distributed Cache

Study 2-3 Interview Patterns per day alongside problem practice.

1 Month (Comprehensive Preparation)

Week 1: Foundations

  • All Introduction chapters
  • All Must-Know Topics
  • All Interview Tips
  • All Concept Deep Dives

Week 2: Technologies and Patterns

  • All Technology Deep Dives (spend more time on: PostgreSQL/MySQL, Redis, Kafka, Elasticsearch)
  • All Interview Patterns

Week 3: Problem Practice (Core)Practice 2 problems per day from these categories:

  • Unique ID Generation
  • Real-Time Communication
  • Social Media Systems
  • Media Streaming
  • Location-Based Services
  • Search and Aggregation

Week 4: Problem Practice (Advanced)Practice 2 problems per day from:

  • E-commerce and Marketplace
  • Payment and Financial Systems
  • Distributed Infrastructure
  • Counting and Ranking
  • Asynchronous Systems
  • Specialized Systems

Spend extra time on problems you found difficult.

2+ Months (Deep Preparation)

If you have more than a month, use the extra time to:

  1. Go deeper on technologies: Read official documentation, understand internal architecture
  2. Practice all problems: Cover every problem in the course
  3. Do mock interviews: Practice explaining your designs out loud
  4. Build small projects: Implement a simple rate limiter or distributed cache
  5. Read engineering blogs: Uber, Netflix, Airbnb, and other companies share their

Final Advice

System design interviews reward depth over breadth. It is better to deeply understand 15 problems than to skim through 50.

Focus on understanding the "why" behind each decision. Why use Kafka instead of RabbitMQ? Why shard by user ID instead of by timestamp? Why push notifications instead of pull?

When you understand the reasoning, you can adapt to any problem, even ones you have never seen before.

Good luck with your preparation!