What Qualities Are Evaluated?

Quality 1: Navigating Ambiguity The first essential quality is your capacity to handle ambiguous scenarios. When presented with a system design question, it may initially be broad. For instance, you might be tasked with designing a travel search platform similar to Kayak. Your objective is to clarify the problem by asking pertinent questions, identifying which use cases to support and which to disregard.

The interviewer is assessing your ability to navigate through the problem space, ascertain requirements, and effectively scope and communicate these requirements while building consensus.

Your objective is to produce: - An artifact that encompasses both functional and non-functional requirements.

Quality 2: Completeness The second quality is completeness. This means you should propose a design that meets essential requirements and offers a reasonable solution. Here are points you might consider discussing.

Quality 3: Discussing Trade-offs and Identifying Limitations The third quality, which complements the second, involves your ability to discuss trade-offs and pinpoint bottlenecks and limitations in your design. System design revolves around trade-offs, as there is rarely a definitive answer. Demonstrating this ability shows your understanding of the frontend landscape and your capacity to leverage established patterns for various issues.

Consider these example topics: - For instance, when discussing content display, you might compare the merits of a paginated table versus infinite scrolling. - In designing a chat application, you could evaluate the pros and cons of using WebSockets versus SSE versus long polling. - When tasked with creating a newspaper layout, discuss the trade-offs between full client rendering, static SSR, SSR with rehydration, and CSR with pre-rendering.

For mid-level to senior roles, you are expected to: - Proactively mention trade-offs and strategies to alleviate bottlenecks, such as scaling your application or addressing security and performance concerns.

Timeline During an Interview

Now, let’s outline the typical timeline of an interview.

Phase 1: Introduction & Problem Presentation Typically, the interview starts with introductions and warm-up questions, followed by the presentation of the system design problem.

Phase 2: Requirements Gathering Once the problem is introduced, spend approximately 5-10 minutes exploring use cases and gathering requirements. Aim to delve into the problem space and determine what to support, narrowing it down to a minimum viable product (MVP) and discussing future additions. Check with the interviewer if this approach is acceptable.

Phase 3: Design Phase The next step is to propose a reasonable design, which usually takes about 15-20 minutes. You should cover several areas, including: 1. Briefly mention the technology stack you intend to use and discuss its advantages and disadvantages. You can steer the conversation toward focusing on the frontend stack and middle tier while assuming the backend will deliver data in a specific format. 2. List the APIs required, detailing the request and response formats. You may need to illustrate data flow, especially for preloading data for initial routing, and discuss the frequency of calls and data model scalability. 3. Dive into the frontend component architecture, detailing hierarchy and composition. Create diagrams to illustrate the state/props of each component, including how properties are passed to child components, state management, and data storage/caching. 4. Discuss potential failure modes and strategies for graceful error handling.

Phase 4: Optimization Discussion & Deep Dive In this segment, you’ll explore specific areas and optimizations in depth. Interviewers may pose probing questions to gauge your knowledge in the frontend domain. Be attentive to hints and adapt your design based on the interviewer's interests while guiding the conversation toward your strengths.

Dos and Don'ts During an Interview

Dos It’s evident to interviewers when candidates are insincere, as they have likely encountered similar questions numerous times. It’s advisable to acknowledge knowledge gaps in certain areas and focus on your strengths, steering the conversation toward those.

Engage in collaborative discussions with the interviewer, adhering to the framework provided in previous slides to navigate discussion points.

Don'ts Avoid rushing into solutions without seeking clarifying questions, as this is a significant red flag.

Other red flags include: 1. Ignoring interviewer feedback. Often, interviewers will interject when they feel the candidate is veering off track; listen to their insights. 2. Responding defensively to questions, which can create a negative impression.

Example Clarifying Questions During an Interview

To conclude, I will share some example clarifying questions you might ask.

Here are several effective clarifying questions to initiate discussions: 1. Who are the users? Are they developers using platforms like GCP or AWS, or are they end-users for a CMS admin portal or a video streaming service? 2. How do users interact with the system? Are they using mobile, desktop, tablets, or screen readers, and do they need offline capabilities? 3. What primary functions do users need the system to perform? This helps define key features/requirements. 4. How many users are expected to use the system? This will inform your scaling strategy. 5. What is the size of the data set? Can it be managed within the webpage, or will a backend server be necessary to facilitate RESTful interactions? 6. What potential issues could arise? This broad question can lead to discussions about failure modes, error handling, testing strategies, observability, and metrics.

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Are you looking for more articles to aid your frontend interview preparation? Here are additional resources:

Frontend Interview Preparation Materials I’ve compiled a list of prep materials that were instrumental in helping me secure a frontend engineer role at MANNG.

Design a Pinterest | Frontend Component Design The Pinterest layout is often referred to as a Masonry layout, which is essentially a grid layout that organizes elements in an aesthetically pleasing manner.

Design a Scrollable Carousel Widget | Frontend System Design Interview Let’s explore a frequently asked question regarding the design of a scrollable carousel widget.

Design an AutoComplete Widget | Frontend System Design Interview Today, we’ll discuss the design of an Autocomplete/Typeahead feature, a common frontend system design interview question.

Design a Data Table Component | Frontend System Design Interview This is the first article in a series dedicated to practicing frontend system design interview questions.