Does Google Ask System Design Interview Questions for L4?

System Design interviews are a critical part of the hiring process for many software engineering roles.

But if we are applying for an L4 (mid-level) position at Google, we might be wondering: Does Google ask System Design interview questions for L4? The short answer: it depends. In this lesson, we will explore the role of an L4 engineer, when and why System Design questions might appear, what kinds of questions to expect, and how to prepare for and handle them effectively.

Let's break down what this means.

Understanding the role of an L4 engineer

L4 engineers at Google are expected to be strong individual contributors. Their primary responsibilities typically include:

• Writing clean, efficient, and maintainable code.

• Solving algorithmic problems effectively.

• Collaborating with teammates to build scalable solutions.

• Contributing to design discussions without necessarily leading them.

Unlike L5 (Senior Engineers), L4s aren’t expected to own large-scale architecture decisions. But that doesn’t mean System Design is completely off the table.

When might System Design for L4 at Google be asked?

While not a guaranteed part of the L4 interview process, System Design questions can still appear under certain conditions:

• Backend-heavy roles: If the team we are interviewing with builds infrastructure or backend systems, interviewers may want to assess our foundational understanding.

• Relevant past experience: If our resume shows prior involvement with scalable systems or design work, it may prompt follow-up questions.

• Team-specific needs: Teams like Google Cloud or Google Ads may ask us to design basic scalable systems, even at L4.

• L4.5 signal: If our interview performance suggests we are close to L5, a lightweight System Design question may be introduced to evaluate our readiness.

What kind of System Design questions could we face?

If System Design is part of our interview, expect scoped-down versions of L5+ questions. These might include:

• Designing a URL shortener: Discussing database schema, scaling reads/writes, and key generation.

• Designing a caching layer: How Can We Reduce Latency? How do we handle invalidation?

• Designing a rate limiter: What techniques would we use to prevent abuse under heavy traffic?

• Designing a messaging queue: Explaining message durability and failure recovery.

Interviewers won’t expect a production-ready blueprint. But we should demonstrate a solid grasp of key concepts like:

• Load balancing

• Data partitioning (sharding)

• Cache strategies

• Read vs. write optimization

How to prepare for System Design as an L4 candidate

Even if System Design doesn’t come up, being ready is always a good bet. Here's how we can prepare effectively:

• Master the fundamentals: Know the CAP theorem, consistency trade-offs, and common design patterns.

• Think in components: Focus on high-level APIs, queues, databases, and load balancers rather than low-level internals.

• Prioritize trade-offs: Be ready to explain why one approach might be better than another depending on scale, latency, or cost.

• Study simplified architectures: Look at how products like YouTube, Twitter, or Google Docs manage scalability.

Common pitfalls in System Design interviews

Here are common mistakes candidates for the Google L4 position make when System Design enters the conversation:

• Jumping into code too soon: Design interviews are about architecture and trade-offs, not implementation.

• Ignoring scale: Even simple services should account for growth over time.

• Failing to communicate trade-offs: A correct answer without justification won’t score well.

• Overengineering: Simplicity wins—don’t introduce components unless they serve a purpose.

How Google evaluates System Design skills at L4

If we are asked a System Design question as an L4 candidate, Google may assess:

• Clarity of thought: Are our ideas structured and easy to follow?

• Scalability: Do we understand how traffic growth affects our design?

• Efficiency: Are our storage, compute, and data flow choices appropriate?

• Trade-offs: Can we defend our decisions under alternative constraints?

The bar is lower than L5, but the signals still matter.

The role of System Design in Google’s tech stack

Even at L4, understanding Google’s infrastructure gives us valuable context. Here are a few systems worth researching:

• Spanner and Bigtable: Distributed databases used across Google’s backend.

• Colossus: Google’s scalable storage system.

• Borg and Kubernetes: The backbone of container orchestration.

While we won’t be expected to design Colossus, knowing how real-world distributed systems work at scale can improve our interview performance.

Real experiences from L4 candidates

Many L4 candidates report that System Design didn’t appear in their interviews, but those who mentioned scalable systems on their resumes were occasionally asked about them. What we can learn:

• Coding dominates: Expect DSA and algorithmic questions to be the focus.

• Lightweight design can appear: Especially if our experience or team requires it.

• Recruiter guidance matters: Ask our recruiter if System Design will be covered so we can focus our prep.

How to handle a design prompt under pressure

If a System Design question surprises us in the interview, here’s how to stay calm and structured:

1. Clarify requirements: Ask questions to scope the problem, identifying what traffic, features, and constraints matter most.

2. Outline high-level components: Think APIs, databases, queues, and caching layers.

3. Talk through trade-offs: Don't aim for a perfect solution; aim to justify our reasoning.

4. Ask for feedback: Show we are collaborative and open to feedback.

Even a basic approach with clear reasoning often scores higher than an incomplete attempt at something complex.

What interviewers care about most in L4 design discussions

For an L4-level System Design discussion, interviewers are primarily evaluating:

• Our ability to break down a problem

• Our comfort with scale and latency trade-offs

• Our communication and collaboration skills

It’s less about architecture mastery and more about clear thinking, sound reasoning, and a willingness to ask the right questions.

How to incorporate System Design into DSA prep

If we are spending most of our time on algorithmic problems, we can still sprinkle in System Design prep:

• Pair one design prompt with every 5–10 coding problems

• Reflect on how algorithms like caching, hashing, or graph traversal appear in systems

• Go through a System Design mock interview once a week to build familiarity

This keeps System Design in our muscle memory without derailing our DSA momentum.

Why lightweight System Design is a strong L4 signal

Even if System Design isn’t required, being able to discuss high-level architecture demonstrates maturity. It signals:

• We think about scale and trade-offs, not just code

• We are comfortable in ambiguous discussions

• We have the potential to grow into L5

It’s about demonstrating thoughtfulness and a willingness to assume more responsibility over time.

Should you focus on System Design for L4 interviews?

For most L4 candidates, the priority is mastering algorithms and coding under pressure. But if we are targeting a backend or infra-heavy team, preparing lightweight System Design discussions is worth the time. At the very least, it demonstrates that we think like engineers, not only coders.

When in doubt, ask the recruiter for clarification. A 30-second clarifying question could save hours of misaligned prep.

Final thoughts

To summarize, while System Design is not a guaranteed component of the Google L4 interview, it can appear, especially for backend-heavy roles or based on our prior experience.

The focus for an L4 candidate is less on complex architecture and more on demonstrating clear thinking, understanding trade-offs, and grasping core concepts. Even if not explicitly tested, preparing lightweight System Design fundamentals is a valuable investment.

It signals a maturity that extends beyond coding and demonstrates readiness for future growth.