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Understanding the Differences between Meta's SWE System Design and Product Design Interviews

By Evan King

Nov 15, 2023

Let me guess, you have the Meta on-site interviews coming up, and your recruiter just offered you a choice between a system design interview and a product design interview. Naturally, you immediately have two questions:

What is the difference between product and system design?
Which one do I have a better chance of doing well in?

Trust me, you're not alone! As a former Staff Engineer at Meta and now co-founder of Hello Interview, I help candidates answer these questions daily.

In this post, I'm going to clearly outline the distinct nuances between system and product design interviews. More importantly, I'll help you determine which type of interview aligns best with your skills and strengths, so you can approach your on-site with confidence and clarity.

Note, If you want to learn more about the Meta interview process, checkout this blog.

What is the System Design Interview?

When you hear "System Design Interview," think big. Really big. This type of interview is all about assessing a candidate's ability to design systems that are not just functional but scalable, reliable, and efficient on a large scale. It's the kind of challenge that excites engineers who love to think about architecture, data flow, and how different pieces of a puzzle fit together to create something robust and user-friendly.

In a system design interview, you're typically going to be evaluated on several key components. Scalability is a big one – can your design handle growth? Whether it's more users, more data, or even more complexity, your system needs to scale gracefully. Reliability is another critical factor. Your system should be trustworthy and deliver consistent performance under various conditions. Efficiency is also crucial; it's all about doing more with less, whether that's less computing power, fewer resources, or in a more cost-effective manner.

So, what kind of questions can you expect? An example might be designing a scalable messaging platform. How would you handle an influx of messages? What about ensuring messages are delivered quickly and reliably? These are the types of problems you'll be asked to solve, focusing not just on the here and now but also on how the system evolves over time.

How to prepare?

Preparing for this interview requires a solid understanding of fundamental concepts and the ability to apply them to hypothetical scenarios. Fortunately, this is the more common of the two interview types, which means there is a plethora of online and print resources. You can browse through my own guide to the system design interview and/or practice on an interactive, magic whiteboard with instant AI feedback.

Resources like "Designing Data-Intensive Applications" by Martin Kleppmann, or "System Design Interview – An Insider's Guide" by Alex Xu, can be incredibly helpful as well. Practice is key – work through different scenarios, sketch out designs, and think through how you would handle various challenges.

How are you evaluated?

Competencies

You're evaluated against 4 main competencies:

Problem navigation: Interviewers are keen to see how well you can dive into the heart of the challenge. They'll look for your ability to pinpoint and tackle the key issues in a system's design. This often involves sorting out the most pressing needs and knowing where to focus your efforts for maximum impact.
Solution design: Here, it's all about your knack for creating system architectures that are not just functional, but scalable and resilient too. The interviewer will observe how you balance the delicate act of juggling performance, scalability, maintenance ease, and cost efficiency in your design.
Technical excellence: You'll be expected to showcase a deep understanding of various tech tools and practices. This is where your expertise really shines – demonstrating that you're not just up to date, but possibly ahead of the curve when it comes to the latest in system design.
Technical communication: One of the key skills you need to demonstrate is your ability to clearly articulate your ideas. It's not just about what you design, but how you explain it. The interviewer will look for clarity in your communication, ensuring you can convey complex ideas in a way that's understandable to everyone, technical background or not.

Remember, these interviews are as much about demonstrating your thought process as they are about the final solution. It's your chance to show off how you think, plan, and execute within a technical framework.

What is the Product Design Interview?

The Product Design Interview at Meta, while very similar to the System Design interview, emphasizes different parts of the system. While System Design zooms out to tackle the architecture and scalability of vast, complex systems, Product Design zooms in on the intricate details of how a service or feature operates and interacts with users. It's perfect for those who thrive on creating tangible, user-centric solutions.

This interview type is a sweet spot for candidates with a knack for full stack or middle-tier backend development. You'll find yourself delving into the realms of API design, data modeling, and client-server interaction, emphasizing how a product or service actually functions rather than how it scales or its underlying infrastructure.

Imagine being asked to design a feature-rich, responsive API for a new social media application, or perhaps, crafting an email server tailored to specific organizational needs. These are typical examples of the challenges posed in a product design interview. Your goal is to showcase your ability to develop features and services that not only meet the functional requirements but also enhance the user experience.

How to Prepare?

Preparation for the Product Design Interview leans heavily on your understanding of APIs, data models, client-server architecture, and user interactions. Start by brushing up on these core concepts. Resources like "Clean Architecture" by Robert C. Martin and "API Design Patterns" by JJ Geewax can offer invaluable insights.

Evaluation Criteria

Whether you opt for the System Design or Product Design interview, you're evaluated against the same four competencies, albeit with nuanced differences in application:

Problem Navigation: This is about how you identify and approach the core issues at hand. In System Design, this means dissecting large-scale, complex systems and pinpointing scalability and reliability challenges. In Product Design, however, it revolves around understanding user needs and how different components of a product interact to fulfill these needs. Your ability to navigate through these challenges and set priorities will be under scrutiny.
Solution Design: Here, your capability to devise effective solutions is evaluated. In System Design interviews, this translates to creating architectures that are scalable, efficient, and robust. In Product Design, the focus shifts to creating functional, user-friendly, and intuitive solutions. The emphasis in Product Design is on the practical implementation of features that directly impact user experience and product functionality.
Technical Excellence: Regardless of the interview type, a high level of technical proficiency is imperative. In System Design, this means demonstrating a thorough understanding of complex, distributed systems and the latest in scalable architecture. In Product Design, it's more about showcasing your expertise in API design, data modeling, and client-server dynamics. It's essential to show that you're not only technically adept but also current with the latest trends and best practices in your field.
Technical Communication: Clear and effective communication is critical in both interview types. However, the content of your communication will vary. In System Design, you'll be explaining complex systems and architectures, often involving abstract concepts. In Product Design, your communication should clearly convey how the product features you design will enhance user experience and meet the product's functional objectives.

In essence, while the fundamental competencies remain consistent across both interview types, their application and focus shift based on whether you're dealing with the broad, architectural challenges of system design or the more user-focused, functional aspects of product design.

Comparing the Differences

	Product Design	System Design
Focus Area	Functional aspects of services/features; user interaction	Architecture and scalability of large systems
Primary Concern	APIs, data modeling, client-server interaction, user experience	Scalability, reliability, efficiency, large-scale infrastructure
Typical Questions	Designing user-centric features (e.g., API or email server design)	Designing large-scale distributed systems (e.g., scalable platforms)
Ideal Candidates	Full stack/middle tier backend developers focusing on user-facing products	Engineers interested in infrastructure, data flow, and architecture
Preparation Focus	Understanding of APIs, client-server architecture, and user needs	Knowledge of system architecture, scalability, and efficiency
Example Resources	"Clean Architecture" by Robert C. Martin, "API Design Patterns" by JJ Geewax	"Designing Data-Intensive Applications" by Martin Kleppmann, "System Design Interview – An Insider's Guide" by Alex Xu

Same Question, Different Focus

Now, here's the fun part: in many cases, the actual question you are asked in the System and Product Design interviews respectively is exactly the same. The difference is simply where you and the interviewer focus your discussion. Additionally, there is a ton of overlap between these two interview types. Just because it's a System Design interview doesn't mean you shouldn't have a user-centric approach and show off your product knowledge. Likewise, just because it's product design doesn't mean you won't still sketch out a high-level backend architecture and articulate your choice of database.

Let's take a look at an example, "Design TicketMaster".

System Design Interview: Designing Ticketmaster

In the System Design interview, your approach to designing a system like Ticketmaster would involve a deep dive into the architectural and scalability challenges. Key areas of focus would include:

Database Sharding/Partitioning: You'd discuss strategies for partitioning the database to efficiently manage and access large volumes of event and user data, ensuring quick response times even under heavy load.
Handling Double Booking: Implementing robust mechanisms, like distributed locks, to prevent issues like double booking of tickets. This would involve a discussion on maintaining data consistency and integrity across distributed systems.
Scalability for High Traffic Events: Designing the system to scale effectively during peak times, such as high-demand event ticket sales. This could involve strategies like load balancing, caching, and efficient use of resources to handle massive spikes in user traffic.
Fault Tolerance and High Availability: Ensuring the system remains operational and maintains a high level of performance and reliability, even in the face of hardware failures or network issues.
Security and Fraud Prevention: Addressing how the system would safeguard against security threats and fraudulent activities, protecting user data and transaction integrity.

You are expected to showcase your understanding of building and maintaining large-scale, fault-tolerant distributed systems, focusing on the technical intricacies and challenges of such an architecture.

Product Design Interview: Designing Ticketmaster

In the Product Design interview, while addressing the same Ticketmaster system, your focus shifts towards the functionality, user experience, and specific features. Key areas of focus would include:

API Design: Developing robust and scalable APIs for tasks like browsing events, handling bookings, and processing payments, with a focus on efficiency and ease of use.
Data Modeling: Discussing how to model data to support functionalities like personalized event recommendations, user preferences, and real-time ticket availability updates.
Client-Server Interaction: Ensuring smooth and efficient communication between the user interface and the server, particularly under varying network conditions and device capabilities.
Feature Implementation: Discussing how to implement and prioritize features like virtual queues for high-demand events, secure payment processing, and user account management.

The emphasis is on how you design features and services from a functional standpoint, focusing on how users interact with the product and how the backend supports these interactions.

So, Which Interview Type is Right For You?

Choosing between a System Design and a Product Design interview hinges on your strengths, as well as the availability and abundance of preparatory resources.

Why Opt for System Design?

Alignment with Experience: If your experience leans more towards large-scale infrastructure, backend systems, or performance optimization, the System Design interview is where you can leverage this expertise. It’s an excellent match for those who have a history of tackling challenges in scalability, reliability, and efficiency in complex systems.
Extensive Resources: The System Design interview preparation benefits from a wealth of resources. Books like "Designing Data-Intensive Applications" by Martin Kleppmann and a long list of online resources like Hello Interview's AI Mocks will get you ready.
Structured Approach: System Design interviews tend to have a more standardized format, allowing for a systematic and predictable preparation process. Knowing the types of questions and scenarios to expect can be a significant advantage.
Broad Relevance: Skills honed for System Design interviews are widely applicable across a variety of engineering roles. This universality means that the effort you put into preparing for this type of interview can benefit your career long-term, beyond just the interview at Meta.

Why Opt for Product Design?

Demonstrate Specific Expertise: If you have strong experience in full-stack or backend development, particularly with user-facing features, the Product Design interview is an ideal platform to showcase these skills. This interview type is specifically suited for those who excel in areas like API design and client-server interaction.
User Experience Focus: This interview type allows you to demonstrate how your technical decisions positively impact the user experience. It's perfect for those passionate about creating intuitive and engaging products that users love.
Targeted Preparation: Although resources for Product Design are less plentiful than for System Design, the available material allows for more focused and in-depth study. Specializing in key areas like API design can give you a distinct edge. Note, the available System Design resources are still of great value for Product Design, as there is a ton of overlap.
Career Alignment: If your career goals involve being intimately involved with product development and feature design, succeeding in a Product Design interview directly aligns with these aspirations. It highlights your ability to not only understand but also contribute significantly to the product development process.

Your decision should align with where your strengths lie and which interview type resonates more with your career goals. If you're still uncertain, leaning towards System Design might be more beneficial due to the abundance of learning resources available.

Regardless of your choice, the most effective preparation strategy is engaging in mock interviews with seasoned experts. At Hello Interview, both myself and my co-founder, along with our team of accomplished coaches, bring a wealth of experience, having conducted these specific types of interviews hundreds of times. We're standing by and ready to help you take your interview game to the next level. You can schedule a mock interview here.

Good luck!

About The Author

Evan, Co-founder of Hello Interview and former Tech Lead at Meta, possesses a unique vantage point, having been on both sides of the tech hiring process. With a track record of conducting hundreds of interviews and securing offers from top tech companies himself, he is now on a mission to help others do the same.

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