Preparing for the Wayfair Software Engineer Interview – Tips and Sample Questions

If you want to work for a company like Wayfair, the interview process should be fun. As you start to think about working here, I want to stress that Wayfair is a great place to work. This starts with our dedication to new ideas and constant testing. As we all try to stay on the cutting edge, we encourage you to take smart risks. This desire comes from a desire to learn new things and give customers the best online experiences possible all the time. Put it all together and what you have is an environment offering you endless opportunities to thrive.

If you want to work for us, it’s our job to show you this side of the company, get to know you better, and make sure we’re a good fit. If you want to know what kind of people we’re looking for, here it is: people who love technology, are dedicated to finding solutions, and are honest about how and why they make decisions. I’ll talk more about this when we talk about how to get hired as a software engineer at Wayfair and what you can do to do well in the process.

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Onsite (or Virtual) Panel

In non-COVID times, we’ll bring you into one of our technology offices to meet with everyone in person. Since early 2020, we’ve been conducting virtual “onsite” interviews using various tools, including Google Meet.

Our in-person and online panels are broken up into four sessions, each of which is based on one of our People Principles:

• Coding and We Drive Results
• App Architecture/Data Modeling and We Are Always Improving
• System Design and We Drive Results
• Team Building/Leadership and We Win Together

At the end of each session, we leave 5-10 minutes for you to ask questions. Some people like to ask the same question at every meeting to get different answers from people all over the company. Others prefer to ask different questions each time. Whatever you decide, this is a great chance for you to find out more about Wayfair and what it’s like to work here.

Coding After a brief introduction, we’ll dive right into a coding challenge. Here we provide a Hackerrank playground for you to work in, and you can use whatever language you are most comfortable with. The playground will execute your code and highlight syntax errors and warnings. There are no tricks here. This is a chance for you to showcase your ability to write simple code, and when complete, our team will be looking at a number of areas.

These include:

• Style: We’ll look at readability, planning ahead, refactoring, and syntax in this section.
• Understanding: We look at how you dealt with clear requirements and uncertainty and talk about technical trade-offs.
• Speed: We want to see how quickly you came up with an idea and wrote code that works.
• Testing: At this point, we look at how to write unit tests and run code as you make changes.
• Last but not least, we want to make sure you fully understand what’s expected of you, explain your options, and respond to coaching.

A Few Tips In the coding stage, it’s crucial that you assess the time complexity of your solution. We know you want to show off your skills and impress the teams, but sometimes it’s better to get code that works for a solution that isn’t the best than to spend too much time looking for the best one. We also suggest breaking code up into functions. I’ve found it easier to understand code that is broken up into smaller pieces.

As soon as you start, you can ask questions and talk out loud as much as you want. The interviewer will be there with you, looking at the same screen you do. As I said at the beginning, this isn’t solely about writing code. You’ll also be tested on how well you can think and be coached, as well as how comfortable you are taking help. It’s always better to ask for help than get stuck and end up with an unfinished solution.

System Design After a similar introduction, we’ll talk about the system you are going to design. Using Hackerrank for video interviews or a whiteboard in the office, we will ask you to design the high-level physical architecture of a full-stack system.

In this session, here’s what we are looking for:

• Collecting requirements: Do you understand the problem, ask questions to make things clearer, and suggest more safety measures than what we’ve given you?
• Part design: Does what you made work as a whole system according to the requirements?
• Protocols and networking: Does what you made show that you know how networks work and how distributed systems work together?
• Size and capacity: Did you build for growth in the right places and show that you know where the bottlenecks will be?
• Operational support: Does your team keep an eye on things and figure out what’s wrong? Do you give your business partners analytics?

App Architecture and Data Modeling Again we’ll start with a brief introduction and then explain the application you’ll be asked to design. Using Hackerrank we will be looking at your ability to design the next level of detail as a logical implementation architecture. From our experience, we’ve found that in the allotted 45 minutes, you will only have time to do a “deep dive” into two out of three main areas (API design, class design, data schema). That being said, you should still have sufficient time to touch on each area.

In this session, we’re looking for:

• API design is the main way that people interact with your app, with input and output being the most important parts.
• Class design: Each class has its own job to do and shows encapsulation, as well as the right way to use inheritance and composition.
• Data schema includes tables, columns, primary and foreign keys, and relationships between tables that make sense.

Team Building and Leadership At this point, the process is almost complete. In this session, there will be a two-way conversation between you and the interviewer. We’ll ask about a project on which you played a significant role. We expect you to explain the business context of the project, what the outcomes were, who was involved, what your role was, what you learned from the project, and what you would do differently next time. We are also very interested in knowing the impact the project has on the business and how you measured success. Similar to the initial phone screen, we suggest you follow the S.T.A.R. method to structure your answers.

Next, we’ll ask you about a difficult relationship you had and how you made it work. Finally, we’ll ask you about a time you had to make a technical decision or plan and come up with a compromise. If you’re interviewing for a management position, we’ll also ask for additional insights and examples. This includes information about how you’ve helped junior and senior engineers advance in their careers, how you’ve kept teams motivated during tough times, how you’ve dealt with employees who didn’t do their jobs well, and how you let go of employees, if necessary.

At this point, your work is done. Now your interviewers will write feedback about their session based on the rubrics explained previously. The interviewer will get feedback from everyone, and then the whole panel will get together to decide if they want to move forward and make you an offer. Either way, your recruiter will be in touch within a few days of your onsite interview. If you get the job, the recruiter will tell you everything you need to know about pay, the role, and more. Please feel free to ask them any questions you have. We know that starting a new job is a big decision, and we’re here to help! All of the hiring managers and engineers are too happy to answer your calls!

Real problems, no tricks

Before diving into the nitty-gritty, there are a few points worth touching on first. For anyone looking to join our engineering team, you need to understand the basics of software engineering. As you might expect, the roles we’re looking to fill get more senior, so we expect candidates to have a wider range of experience. As any good engineer knows, you can use Google to look up syntax or function names. For coding challenges, you can choose the language you want to use. Regardless, it comes down to two areas.

• Before you can do well at Wayfair, you need to know the basics of computer science and programming. These include data structures, and time and space complexity. These are essential to all roles.
• Next comes your critical thinking skills. You decide how much or how little to talk out loud. We understand people have different communication styles. In fact, we welcome this range of styles. Before you go any further, you should be able to clearly explain your solution(s). Take a moment to think about what your solution will look like on Wayfair’s scale, with millions of users.

I’d also like to talk about bias in the hiring process and what Wayfair does to make sure all of its interactions with job candidates are fair and based on facts. For Wayfair to be Diverse, Fair, and Inclusive, we work hard to make this process as objective as possible because we know everyone has unconscious biases.

We do this by making sure that all of our interviewers go through the same training so that they all use the same approach. We have a rubric for each step that tells our interviewers how to rate the candidate in that part. Once these talks are over, interviewers give candidates their feedback, and then they start talking with the rest of the interview panel. These steps are built into the feedback forms, which remind everyone that they need to use objective statements and evidence from the interview in their answer.

With that, let’s move on to the process.

There are generally five parts to our software engineering interviews. These include:

• Recruiter Call
• Technical Screen
• Phone Screen (depends on level)
• Onsite Panel
• Fit & Sell Call(s)

Here, the recruiter will give you an overview of Wayfair’s business and the Wayfair Technology team. Next, they will talk about some of the roles we have open and, most importantly, how they can match your skills with one (or more!) of our open positions. I encourage everyone to ask questions because this will help us find the right fit for you.

A Wayfair Engineer will do a technical assessment of your coding skills and system design knowledge by asking questions about scaling, capacity, networking, and component design. This is the technical part of the process. We also use other assessment models depending on the role. Like a case study, which helps us figure out how well your technical skills match up with what we need, Either way, your recruiter will let you know exactly what to expect and how to best prepare. Usually, these screens give us a quick idea of how good you are at things like coding and system design (you can learn more about this in the “Onsite Panel” section below).

In general, we use phone screening to look at your softer skills and your overall ability to drive impactful solutions. You should also be prepared to answer technical questions about your work and the thought process behind the decisions you have made. We suggest using the S.T.A.R. (Situation, Task, Action, Result) method as a guide for structuring your responses to questions in this round.

Wayfair Interview question – Board, Tiles

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