The technical hiring process depends heavily on the System Design interview process, especially for roles such as software engineers, system architects, and technical leads. The basics are a given, but you must be familiar with modern trends in your field beyond the surface level.

Most importantly, you must prove your skills and experience by facing off in the System Design interview with confidence and preparation. Big company or small, there is a method to the System Design interview that must be cracked before you walk through the door.

System design interview fundamentals

System Design interviews are built to hone in on your ability to design scalable, efficient, and maintainable systems. There are various factors involved in the process, so here’s a quick rundown of key concepts that you should be clear on before moving forward.

Architecture patterns

Monolithic architecture is a tech reality of the past, and most modern services use microservice architecture. Microservices are applications decomposed into loosely coupled, independently deployable services. They are used in large-scale, complex applications and require frequent updates.

Microservices involve smaller, efficient teams that build independently from the broader system. They have proven resilient, highly scalable, deployable independently, and capable of evolving quickly. Since microservice architecture involves small, autonomous services, each is self-contained and has a separate codebase.

API design

Understanding API design principles in the context of modern distributed systems is important if you are to perform well in a system design interview. You must understand where different services need to communicate effectively and how they interact.

You should be familiar with various APIs, including REST (Representational State Transfer), GraphQL, gRPC, SOAP (Simple Object Access Protocol), and WebSockets. In addition, you must be clear about the different design principles, including consistency, versioning, statelessness, security, error handling, pagination, rate limiting, and documentation.

Knowing how the design process works is also crucial, from identifying resources, defining endpoints, and creating data models to the caching strategies, scaling, and authentication and authorization processes.

Trade-off analysis

Trade-off analysis has everything to do with your ability to make informed decisions when faced with multiple design options. Every System Design choice must be made with caution and a complete understanding of the system's functional and non-functional requirements.

In a System Design interview, you must be prepared to showcase the skill set necessary to guide your trade-offs by knowing when to prioritize certain system requirements over others and why.

Some examples of key trade-offs are the following:

• Scalability vs. consistency
• Performance vs. complexity
• Availability vs. partition tolerance
• Cost vs. performance

Modern trends

The rapid pace with which technology evolves waits for no one, and what might have been relevant to know for a System Design interview a couple of years ago might already be outdated. Below, you will find specific concepts that pertain to particular industry developments, on which your knowledge may be judged during a System Design interview.

Cloud-native designs

Cloud-native refers to the approach of building and running applications that take advantage of both built-in security features and the CSP shared responsibility model. They are built to exploit a cloud environment's scale, resilience, cost-efficiency, and portability.

Containerization

Containerization is a core software deployment process that packages an application and its dependencies into a standardized container unit. These containers are consistently deployed across various environments, ensuring the application runs the same no matter where it is executed.

For your System Design interview, you must understand Docker and Kubernetes and how they deploy and manage containerized applications. Concepts such as container orchestration, scaling, and service mesh will surely arise.

Serverless architecture

Serverless architecture is a cloud-native design model in which developers build and run applications without managing infrastructure. The application runs on servers, but it is managed by computing providers and platforms such as AWS, Lambda, Google Cloud Functions, Azure Functions, etc. Be familiar with trade-offs such as cold start latency, throttling, automatic scaling, and execution limits.

CI/CD pipeline

Within cloud-native design, a CI/CD (Continuous Integration/Continuous Deployment) pipeline is a set of automated processes that allow for rapid and reliable development, testing, and deployment of applications. During a System Design interview, it is essential to be informed about tools such as Jenkins, GitLab CI, and CircleCI.

AI/ML integration

Before your System Design interview, you should understand three key points regarding AI/ML integration: model serving, feature stores, and ethical AI.

Model serving is developing a trained machine-learning model available for use in real-world applications. You must understand how to deploy and scale ML models in production, which involves model versioning, monitoring, and A/B testing.

In AI/ML integration, a feature store is a centralized repository designed to manage, store, and consistently serve ML features across the entire ML lifecycle. In 2024, tools like Feast and Tecton are being pushed more to the forefront of operations.

With the rapid integration of AI and machine learning in tech industry operations, acute awareness and knowledge of ethical AI are crucial. It is a topic of contention that is bound to come up in a System Design interview. Ethical AI in AI/ML integration is designing, developing, and deploying AI systems that align with moral principles. Bias mitigation and explainability must be understood thoroughly.

Security and privacy

In 2024, there is a growing concern regarding data breaches, cyber threats and regulatory compliance, and knowing about strong authentication mechanisms is important to know for a System Design interview.

Data encryption strategies at rest and in transit, understanding TLS, end-to-end encryption, and other key management practices are just some of the concepts you must be proficient in. In regard to data privacy, you must be aware of global and regional data protection laws like GDPR, CCPA, and HIPPA.

Modern authentication protocols to be familiar with include OAuth 2.0, OpenID Connect, and SAML. Moreover, RBAC (Role-Based Access Control) and a zero trust approach (no entity inside or outside a network is trusted) are other concepts to have a clear grasp on.

System design interview structure

System design interviews have grown in complexity, reflecting the advanced nature of modern software systems. Here is a brief overview of specific interview components you should expect, and prepare for.

Open-ended questions

In System Design interviews, open-ended questions function to assess your critical thinking abilities, consider trade-offs, and design scalable, maintainable systems.

• Ambiguity and scope As the term suggests, open-ended questions are broad and lack specific details to give the candidate space to showcase their skill set. You won’t get further guidance beyond the main premise, for example, “Decide a social media platform.” How you go about it will be up to you.

The interviewer will evaluate how you handle the problem with limited guidance, what questions you ask in response, and your ability to transform the problem into something more manageable within a given timeframe.

• Exploring multiple solutions Some questions you will be asked will not have a single correct answer. The interviewer will judge whether you have the capacity to think outside the box and to what extent you explore various architectural choices while considering their pros and cons.

Employing a comparison strategy, such as ‘microservices vs. monolithic architectures,’ may help streamline your answer and thoroughly explain your reasoning.

Whiteboarding/Diagramming

To effectively communicate your thought process and ideas, visuals matter and that’s what whiteboard and diagramming provide. The objective is to break down complex ideas, and convey a structured thought process to the interviewers.

Whiteboarding and diagramming also allow for real-time collaboration as interviewers can ask questions, and you can further build on the ideas in your answers. Remember to start simple, and as you build your diagram in iterations, you clearly label all components on display.

Evaluation criteria

Here’s a breakdown of key evaluation criteria you will be judged on during a System Design interview. Through these points, you can identify the areas where your weaknesses lie and address them.

• Clarity of thought
  How well you understand what’s being asked and your clarity with the requirements of the system. This includes both functional and non-functional requirements. The more organized you are, the better you will be able to identify and articulate assumptions and constraints related to System Design.

• Design approach and architecture
  Your ability to create a high-level design that outlines major components and interactions will be evaluated–this includes system diagrams, data flow, and component interactions. Scalability is another criterion and involves how well the design scales with increased load. In addition, your design’s ability to promote flexibility is another important factor.

• Efficiency and performance
  The system you design must showcase minimized latency and optimization throughout in the system. How well you implement caching mechanisms, and your knowledge of caching strategies to reduce load and improve performance will also be evaluated.

• Communication
  Your ability to communicate your ideas clearly and logically will allow the interviewers to comprehend your knowledge, skills, and confidence. In short, your expertise needs a leg to stand on, and how well you express your answers will play a crucial role in acing the System Design interview.

Final words

You will find how System Design interviews in 2024 blend foundational knowledge, practical experience, and a sharp awareness of modern trends. While you are in the middle of your preparation process, it is necessary to incorporate a mix of study, practice, real-world experience, and honing your communication skills.

Educative’s System Design Interview Prep Handbook is available to help streamline your study routine. It encompasses all the knowledge bases you need to cover to succeed; problem strategies, as well as real-world design process simulations.