Why System Design Is the Hardest Part of FAANG Interviews (And How to Master It)

Mastering scalability, trade-offs, and communication: the keys to cracking FAANG’s toughest interview round.

credit — ByteByteGo

Hello guys, If you’ve ever dreamed of working at FAANG companies (Facebook, Amazon, Apple, Netflix, Google), you’ve probably heard the horror stories about their interview process.

Multiple coding rounds, behavioral interviews, and the infamous on-site “loop.” But ask any engineer who has been through it, and they’ll tell you: system design is the toughest part of the FAANG interview journey.

Unlike coding rounds — where there’s usually a clear problem statement, inputs, outputs, and a “correct” answer — system design interviews are intentionally open-ended.

You’re asked to design something like WhatsApp, Instagram, a URL shortener, or a scalable news feed. There’s no single right answer. Instead, interviewers want to see how you think, communicate, trade off options, and scale real-world systems.

In this article, I’ll break down:

  • Why system design is so challenging?
  • The unique skills it requires (that coding alone can’t cover)
  • How to approach system design interviews strategically
  • The best resources to master system design — including why I recommend ByteByteGo and Codemia.io , two of the most trusted platforms for FAANG interview prep.

If you already know about them, now is the good time to join because they are also offering 50% discount on their lifetime plan, I just bought one as it provides the best value for not just System design interview but also coding interview in general.

System Design · Coding · Behavioral · Machine Learning Interviews

Codemia.io is also offering 65% discount now on their lifetime plan and I highly recommend to join them to get the online practice you would need to hone your System design skills.

Here is the link to join — 65% OFF on Codemia.io Lifetime Plan

Master System Design Interviews Through Active Practice

Why System Design Is the Hardest Part of FAANG Interviews?

Now, let’s see why System Design is so hard to master and why its the biggest hurdle in your FAANG dream.

1. It’s Open-Ended by Design

A coding interview might ask you to implement LRU Cache. You either get it right, or you don’t.

A system design interview, on the other hand, might say: “Design a cache system for a social media platform with millions of users.”

Now you’re on your own: Do you use Redis or Memcached? How do you handle cache invalidation? What about consistency across regions?

There’s no fixed answer — just trade-offs. And this is where many candidates stumble.

2. It Tests Breadth and Depth Simultaneously

In one 45-minute session, you may need to talk about:

  • Databases (SQL vs NoSQL)
  • Scaling with sharding and replication
  • Message queues and event-driven design
  • Load balancing and fault tolerance
  • Security considerations

Most developers don’t use all of these every day. FAANG interviewers want to see whether you understand both high-level architecture and low-level implementation details.

3. Real-World Complexity, Simulated in 60 Minutes

The reality is that designing a production-ready service takes months of brainstorming, prototyping, and iteration.

But in an interview, you have less than an hour.

That pressure — combined with the need to communicate clearly, draw diagrams, and make decisions fast — makes this round particularly brutal.

4. Communication is as Important as Knowledge

Many strong engineers fail system design interviews not because they lack technical knowledge, but because they can’t structure their thoughts or explain trade-offs clearly.

Interviewers look for:

  • Do you clarify requirements first?
  • Do you outline a high-level design before diving into details?
  • Do you justify trade-offs with reasoning instead of buzzwords?

System design is as much about storytelling as it is about architecture and that’s where practice makes a lot of difference and I trust codemia.io for that practice.

This platform provides you all the tools you need to answer System design question online including diagram tool, AI chatbot and expert review.

If you quickly want to get your act together, just solve 5 to 10 system design question on this site and compare you solution with the expert solution.

They are also offering 65% discount now on their lifetime plan and I highly recommend to join them .

Why Just Knowing Concepts Isn’t Enough?

Reading about CAP theorem, consistent hashing, consensus algorithms, or database indexing is not the same as applying them under pressure. In fact, one of the biggest misconceptions is that system design can be mastered by just reading theory.

Here’s why that doesn’t work:

  • You need to practice applying patterns (like leader election, partitioning, CQRS).
  • You need exposure to real-world case studies — e.g., how Netflix does streaming or how WhatsApp handles billions of messages daily.
  • You need feedback and iteration — because system design is rarely perfect on the first attempt.

That’s why structured practice + visual learning is the only way to truly master this interview area and that’s where ByteByteGo excels. Their visual guides are best way to master any System Design concepts in depth in very quick time.

Here is an example of that from ByteByteGo to learn CQRS pattern in depth

How to Prepare for FAANG System Design Interviews?

If you’re serious about landing a FAANG role, here’s the roadmap I recommend:

1. Master the Fundamentals

  • Networking basics: DNS, TCP/IP, HTTP, load balancing
  • Databases: Indexes, sharding, replication, transactions, consistency models
  • Caching: Strategies, eviction, invalidation
  • Queues & Pub/Sub: Kafka, RabbitMQ, SQS
  • Storage: Blob stores, file systems, distributed storage

2. Learn Common System Design Patterns

3. Study Real-World Case Studies

Don’t just learn theory — learn how big companies actually do it:

How Payment System Works?

4. Practice Out Loud

Grab a whiteboard or use a collaborative diagramming tool. Pick a problem (e.g., design a URL shortener), and walk through your solution out loud. Structure your answer as if you’re already in the interview.

You can also use platforms like codemia.io to practice System Design problems online, they also have a big collection of popular questions and a company wide database as shown below:

5. Use the Right Resources

This is where I personally recommend ByteByteGo and Codemia.io, two of my favorite resource to crack any System Design interview, while ByteByteGo gives you all the theory, visual explanation and a structured way to prepare, Codemia.io gives you much needed platform and online practice.

Why ByteByteGo Is the Best Resource for System Design Prep?

ByteByteGo, created by Alex Xu (author of the bestselling System Design Interview book series), has become the gold standard for engineers preparing for FAANG interviews. Here’s why:

1. Visual Learning

Unlike text-heavy books, ByteByteGo explains concepts with diagrams, animations, and step-by-step breakdowns. This makes complex topics like sharding, leader election, or consensus algorithms much easier to grasp.

2. Real-World Case Studies

Learn how companies like Netflix, WhatsApp, and Uber design their systems — with detailed diagrams and trade-offs explained.

3. Always Updated

New patterns, architectures, and real-world examples are added regularly — including cutting-edge topics like Generative AI system design.

4. Comprehensive Coverage

Goes beyond just system design: includes coding interview patterns, OOP design, ML system design, and GenAI system design — all in one subscription.

5. Affordable Lifetime Plan

Right now, ByteByteGo is offering a rare 50% discount on their annual and lifetime plans. The lifetime plan in particular is a no-brainer if you’re serious about your career. You pay once, and get lifetime access (including all future updates).

👉 Check the 50% OFF Lifetime Plan Here

Annual Plan vs. Lifetime Plan

  • Annual Plan: Lower upfront cost, good if you only need short-term access.
  • Lifetime Plan: Pay once, get access forever — perfect if you expect to revisit system design multiple times in your career (and let’s be honest, you will).

Considering FAANG interviews happen at multiple points in your career — promotions, role switches, or just exploring opportunities — the lifetime plan pays for itself after two years.

My Take: How to Finally Master System Design?

There is no doubt that System design interviews are hard. They’re supposed to be. They test whether you can think like a senior engineer, make trade-offs, and communicate effectively under pressure.

But with structured learning, repeated practice, and the right resources, you can absolutely master them.

If you want the fastest, most visual, and most updated path to mastery, my recommendation is clear:

  • Pick up ByteByteGo’s Lifetime Plan (50% OFF now)
  • Combine it with Codemia.io (65% discount now) for practice problems and mock interviews
  • Keep refining your ability to explain your thinking clearly

This way, you’re not just preparing for FAANG interviews — you’re building a skill set that will make you a stronger engineer throughout your career.

👉 Start learning with ByteByteGo here

Final Thoughts

If coding interviews are about showing your technical precision, system design interviews are about showing your engineering wisdom. That’s why they’re the hardest — and the most important — part of FAANG interviews.

The good news? With the right preparation, you can absolutely ace them.

And if you want a resource that grows with you, keeps you updated, and gives you crystal-clear explanations of even the most complex topics, ByteByteGo is hands down the best choice.

Your next FAANG role could depend on your ability to master system design. Don’t leave it to chance.

👉 Check out ByteByteGo’s 50% OFF Lifetime Plan today

System Design · Coding · Behavioral · Machine Learning Interviews

You can also watch their YouTube video “How to Crack Any System Design Interview” to learn more about cracking System Design for FAANG interviews.

https://medium.com/media/ffca794d3743e78aba398b847340fe1f/href

Other System Design and Coding Interview and Resources you may like

All the best for your System design and OOP Design Interviews, if you have any doubts or questions, feel free to ask in the comments.

P. S. — If you just want to do one thing at this moment, join ByteByteGo and start learning software architecture fundamentals and you will thank me later. It’s one of the most comprehensive resource for coding interview now.

System Design · Coding · Behavioral · Machine Learning Interviews

Why System Design Is the Hardest Part of FAANG Interviews (And How to Master It) was originally published in Javarevisited on Medium, where people are continuing the conversation by highlighting and responding to this story.

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