How I Mastered System Design for Interviews?

From freezing up completely to confidently designing systems at FAANG-level interviews

credit — Designgurus.io

Let me be brutally honest with you.

There was a time when “system design interview” were the four most terrifying words in tech.

I’d see a system design round on my interview schedule and think: “This is for principal engineers, not for me.”

I was completely wrong.

Because six months ago, in a MAANG interview, they asked me:

“Design a URL shortener like bit.ly that can handle 100 million URLs per day.” (solution)

And I nailed it.

I talked about load balancers, database sharding, caching strategies, and even discussed the trade-offs between different hashing approaches.

But two years ago? I would have frozen up completely.

The wake-up call came during my first FAANG interview at Amazon when they asked:

“Design a chat system like WhatsApp?”

I started talking about REST APIs.

I mentioned a MySQL database.

Then… awkward silence for 30 minutes.

No clue about WebSockets, no idea about message queues, not even sure how to handle the scale of billions of messages.

I didn’t get the job.

That day I decided I would never feel that helpless in a system design interview again.

Here’s how I went from being completely terrified of system design questions to consistently passing system design rounds at top tech companies, and even helping my colleagues prepare for their own interviews.

1. First, I Accepted That System Design Interviews Are Different and That’s Okay

System design interviews are unlike any other technical interview.

People throw around terms like “horizontal scaling”, “eventual consistency”, “CAP theorem”, “microservices architecture”…

At first, it made me feel inadequate. But then I realized:

System design interviews test your engineering thinking, not your memorization.

Unlike coding interviews where there’s often one optimal solution, system design is about:

  • Understanding requirements and constraints
  • Making reasonable trade-off decisions
  • Communicating your thought process clearly
  • Designing for scale, reliability, and maintainability

Once I accepted that this was more about structured thinking than perfect answers, everything clicked.

I stopped trying to memorize solutions and focused on developing a systematic approach.

2. I Built My Foundation With the Right Resources

System design knowledge comes from understanding distributed systems concepts, not just interview prep.

Here’s how I structured my learning:

a) The Must-Read Books

The foundational text that changed everything:

Designing Data-Intensive Applications: The Big Ideas Behind Reliable, Scalable, and Maintainable Systems

The interview-specific guides:

System Design Interview – An insider’s guide

b) Comprehensive Online Courses

The courses that actually prepared me:

System Design · Coding · Behavioral · Machine Learning Interviews

Tech Interview Preparation – System Design, Coding & Behavioral Courses | Design Gurus

Grokking System Design Interview: Patterns & Mock Interviews

Learn System Design and Ace Your System Design Interview | Learn from Ex-FAANG Engineers

Master the Coding Interview: System Design + Architecture | Zero To Mastery

Top 10 Udemy Courses to Learn System Design and Software Architecture in 2025

c) Specialized Interview Platforms

For focused interview practice:

  • Exponent — Mock interviews with real feedback from ex-FAANG interviewers

Interview prep for product, engineering, data science, and more – Exponent

  • Codemia — AI-powered interview practice with personalized feedback
  • BugFree.ai — Practice with realistic interview scenarios

Master System Design & Behavioral Interviews Like Leetcode

Full transparency: These are affiliate links, meaning I earn a small commission if you purchase through them, at no extra cost to you. I only recommend resources I’ve personally used and found valuable.

3. I Developed a Consistent Framework for Every Interview

The breakthrough came when I realized successful system design interviews follow a pattern.

My 7-step framework:

Step 1: Clarify Requirements (5 minutes)

  • What are the functional requirements?
  • What’s the expected scale (users, requests, data)?
  • What are the non-functional requirements (latency, availability)?

Step 2: Estimate Scale (5 minutes)

  • How many users/requests per second?
  • How much data storage needed?
  • What’s the read/write ratio?

Step 3: High-Level Design (10 minutes)

  • Draw the basic components
  • Show data flow between components
  • Keep it simple initially

Step 4: Database Design (10 minutes)

  • Choose SQL vs NoSQL and justify
  • Design the schema
  • Discuss indexing strategies

Step 5: Deep Dive (15 minutes)

  • Pick 2–3 components to elaborate
  • Discuss algorithms and data structures
  • Address bottlenecks and optimizations

Step 6: Scale the Design (10 minutes)

  • Add load balancers, caches, CDNs
  • Discuss sharding and replication
  • Address failure scenarios

Step 7: Monitoring and Alerting (5 minutes)

  • What metrics to track?
  • How to detect issues?
  • Logging and debugging strategies

If you want to see them action then checkout this solution of URL shortener where this framework is applied step by step.

You can also use System Design templates like the ones given by Designgurus.io to architect your solution and explain them during interview as shown below

4. I Practiced With Real Interview Questions from Top Companies

Theory without practice is useless. I needed to simulate real interview conditions.

Essential practice platforms:

  • Codemia.io — Curated questions from actual FAANG interviews
  • BugFree.ai — In-depth analysis of popular system design questions
  • Exponent— collection of questiosn from both FAANG and MANGO companies.

Free resources I used extensively:

Questions I practiced obsessively:

For each question, I’d:

  • Time myself (45–60 minutes)
  • Draw everything out on a whiteboard
  • Explain my reasoning out loud
  • Review optimal solutions afterward
  • Redo the same question a week later

5. I Learned From Real System Design Experts

Reading about system design is good. Watching experts think through problems is transformative.

YouTube channels that became my university:

  • ByteByteGo — Visual system design breakdowns
  • Exponent — solution of popular System Design problems explained
  • Gaurav Sen — Explains complex systems with simple examples
  • System Design Interview — Mock interviews with detailed explanations
  • Tech Dummies — Real-world system design case studies

Podcasts and newsletters:

  • High Scalability blog — Real system architectures from top companies
  • AWS Architecture Center — Cloud-native design patterns
  • Google Cloud Architecture Framework — Best practices and case studies

Following senior engineers:

  • Twitter/X accounts of principal engineers at FAANG
  • Engineering blogs from Netflix, Uber, Airbnb, Discord
  • System design posts on LinkedIn from industry veterans

6. I Applied System Design Thinking at Work

The real learning happened when I started seeing system design patterns in my day job.

Projects where I applied interview concepts:

Microservices Migration

  • Broke down a monolith using domain-driven design
  • Implemented circuit breakers and retry logic
  • Set up proper monitoring and alerting

Database Scaling Challenge

  • Identified bottlenecks in our MySQL setup
  • Implemented read replicas and connection pooling
  • Designed a caching layer with Redis

API Rate Limiting

  • Designed a distributed rate limiting system
  • Used sliding window algorithms
  • Implemented proper error handling and backoff

Each real-world application deepened my understanding of trade-offs, failure scenarios, and operational concerns that pure interview prep couldn’t teach.

7. I Started Mock Interviewing Others (This Was Huge)

Teaching system design to others revealed gaps in my own knowledge.

How I practiced teaching:

  • Conducted mock interviews for colleagues
  • Explained system architectures in team meetings
  • Created internal documentation for complex systems
  • Mentored junior engineers on distributed systems concepts

Tools that helped with mock interviews:

  • Exponent — Allows you to do peer-to-peer mock interview
  • Zoom whiteboarding — Simulated remote interview conditions
  • Draw.io — For creating system design diagrams

Every time I explained load balancing or database sharding, I discovered nuances I hadn’t considered before.

If I couldn’t draw it and explain it clearly, I didn’t understand it well enough.

My Honest Interview Success Strategy

After 50+ practice sessions and 8 real system design interviews, here’s what actually works:

Before the interview:

  • Practice the same 10 core questions until you can do them in your sleep
  • Time yourself religiously — 45 minutes goes by incredibly fast
  • Practice drawing and talking simultaneously
  • Review failure scenarios for each component

During the interview:

  • Always start with requirements clarification
  • Think out loud — silence is your enemy
  • Draw first, optimize later
  • Admit when you don’t know something
  • Ask for feedback and iterate

Common mistakes I learned to avoid:

  • Jumping into implementation details too early
  • Not considering the scale requirements
  • Forgetting to discuss trade-offs
  • Not leaving time for failure scenarios
  • Being too rigid with one solution

The Resources That Made the Difference

If you can only invest in a few resources, start with these:

Essential Foundation:

  1. “Designing Data-Intensive Applications” — Read this first
  2. ByteByteGo Course — Visual learning that sticks
  3. System Design Interview Book — Interview-specific preparation

For Serious Preparation:

  1. DesignGuru — Comprehensive curriculum
  2. Exponent — Mock interview practice
  3. Educative — Interactive learning

For Continuous Learning:

  1. Free System Design Resources — Ongoing education
  2. GitHub Collection — Community resources

Final Advice: System Design is a Learnable Skill

System design interviews seem intimidating, but they’re actually more predictable than coding interviews.

The patterns are finite:

  • Load balancing strategies
  • Database scaling approaches
  • Caching patterns
  • Messaging queue architectures
  • CDN and geo-distribution

Master these building blocks, and you can design any system.

You don’t need 10 years of distributed systems experience.

You don’t need to have built systems at Google scale.

You just need to:

  • Understand the fundamental concepts
  • Practice structured thinking
  • Learn to communicate trade-offs clearly
  • Simulate real interview conditions
  • Stay calm and think step by step

Start Your System Design Mastery Today

Begin with understanding how basic systems work.

End with confidently designing systems that serve millions of users.

The journey takes 3–6 months of focused study, but the career impact lasts forever.

One concept at a time. One practice session at a time. One interview at a time.

System design mastery isn’t just about interviews — it’s about becoming the engineer who can architect the future.

Other System Design and Coding Interview and Resources you may like

All the best for your Coding Interviews, if you have any doubts or questions, feel free to ask in the comments.

P. S. — If you want to do just one thing now then I would highly recommend you to join ByteByteGo and System Design Concepts and practice coding interviews you will thank me later. It’s one of the most comprehensive resource for not just coding interview but also for senior engineers to get better at their work. They are also offering 50% Discount now.

System Design · Coding · Behavioral · Machine Learning Interviews

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