System Design Experience Guide - From a Senior FAANG Engineer

My perspective on building system design skills through work experience and effective interview preparation.

Building System Design Experience at Work

The Reality: System Design is Broad and Deep

Let me be honest - system design can't be mastered quickly. The best way to build these skills is through real work experience: doing projects and learning from other teams' designs. These are battle-tested industrial solutions that actually work.

Personal Example: I've led several system designs that happened to be classic interview questions. During the design phase, I dove deep into:

• Implementation details of various solutions
• Pros and cons of each approach
• Hardware parameters and load test results
• Real-world pitfalls and lessons learned

This hands-on experience is far more valuable than online tutorials or YouTube videos. When these topics come up in interviews, I can lead the discussion and cover aspects even interviewers haven't considered.

Career Strategy for Building Design Skills

For Mid-Level Engineers:

• System design interviews test breadth more than depth
• You can pass without knowing every technology detail
• Focus on providing sensible solutions

For Senior+ Engineers:

• Both breadth AND depth matter
• You need data and experience to support your solutions
• Not knowing a key area can fail the interview

Career Progression Tips:

• Early career: Switch teams/projects to build breadth
• Later career: Stay in one domain to build depth
• You'll discover many concepts are interconnected
• If your company doesn't offer growth opportunities, consider if it's the right fit

Learning and Preparing for System Design Interviews

Foundation Resources

1. Designing Data-Intensive Applications (DDIA)

• Often called the "bible" but really it's an entry-level foundation book
• Excellent for understanding how industry handles distributed data
• Core focus on data - which is the heart of system design
• Won't directly solve interview problems but builds crucial understanding
• Weak on batch/stream processing - needs supplementation

2. System Design Primer

• Good for beginners learning concepts
• Warning: Some content has errors since it's crowd-sourced
• Don't memorize - think critically about the content

3. Essential Papers

• Google's Big Three: GFS, MapReduce, Bigtable
• Amazon's DynamoDB
• Various summaries and notes available online

4. Other Books

• "Designing Distributed Systems" - decent but not as good as above
• For batch/stream processing: Consider Kafka, Flink specific books
• "Real-Time Analytics"

Learning from Real Cases

Best Sources:

• If you're at a big tech company, study other teams' production designs
• Google, Meta, Amazon are goldmines for real-world examples
• Industrial solutions vs. online guesses - huge difference

Resource Quality Guide

Watchable but Limited:

• Grokking: Basic concepts and ID generator example are okay, skip the rest
• Alex Xu's Books:
  • Book 1: Too shallow, similar to Grokking
  • Book 2: Better with more content but inconsistent quality
  • Feels like different authors or compiled from various sources
  • Some sections pad word count while skipping important discussions
  • Still worth buying due to lack of better resources

System Design Interview (YouTube):

• Rate Limiter video is good
• Skip the Top K solution - outdated approach that will fail interviews
• Recently selling courses - will update after reviewing

Interview Tips

Core Understanding

Most system design interviews revolve around:

1. Requirements → What data do you need?
2. Data characteristics → Size, patterns, access methods
3. Data handling → Storage, retrieval, integrity

This is why DDIA is valuable - it's all about data-centric design.

Drawing and Explaining

Interviewers want to see:

• Reasonable infrastructure choices
• Correct data flow
• Clear thinking process

Pattern Recognition

Many design problems share common patterns:

• Group chat ≈ Multiplayer card games (similar data handling)
• With experience, you'll see recurring patterns
• Market may introduce new problems as it gets more competitive

Capacity Estimation

In real work: Calculate precisely for scalability and cost In interviews: Order of magnitude is usually enough

• TB vs GB?
• Million vs thousand QPS?
• These determine your technical choices

Senior+ tip: If you can casually calculate exact numbers and provide specific infrastructure choices with cost analysis, it's a major plus.

Luck Factor

Sometimes you get difficult or egotistical interviewers - no technique helps there 😅

Recommended Case Studies

Good examples should clearly address schema design - if they gloss over data modeling, the entire architecture is questionable.

Quality Examples

1. Rate Limiter

• Popular YouTube tutorial on rate limiting
• Solid for interviews
• Schema is simple: store numbers and identity
• Missing: Design is not one-way - can use local rate limiters as safeguards
• Think deeper: CPU/memory-based rate limiting, N² mesh problems

2. Chat Application

• https://towardsdataschience.com/ace-your-system-design-interview-chat-application-3f34fd5b85d0
• Written by a new grad but better than many "expert" solutions
• Good data handling for entry-level
• Some design flaws but would pass interview

3. Job Scheduling System

• https://towardsdataschience.com/ace-your-system-design-interview-job-scheduling-system-b25693817950
• Same author as above, similar quality

Finding More Resources

• InfoQ YouTube Channel: Tech talks on classic architectures (e.g., Slack)
• Company Tech Blogs: Uber, Dropbox, and other major tech companies
• Note: Companies are conservative about data details - you need to infer their schema designs

Final Thoughts

The key to system design mastery is accumulating real experience and learning from actual industrial solutions. While interview prep resources help, nothing beats understanding how systems work in production.

Remember: Good solutions should resemble what you'd actually build at work, not theoretical guesses.

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Hope this helps! Feel free to share better resources and experiences. Let's help each other navigate this challenging but rewarding field.