Coupang Data Engineer Interview Questions + Guide in 2024

Coupang is one of the fastest-growing e-commerce companies and a dominant force in South Korean commerce. Born out of a mission to make shopping, eating, and living easier, we are redefining the industry with our innovative approach. Our startup culture, backed by the resources of a global company, allows us to launch new services rapidly and empower bold, ambitious individuals to make a hands-on impact.

This guide will provide tips and recurring Coupang data engineer interview questions to bolster your prep and increase your chances of landing the role. Let’s get started!

The interview process usually depends on the role and seniority, however, you can expect the following on a Coupang data engineer interview:

Recruiter/Hiring Manager Call Screening

Upon shortlisting, a recruiter from Coupang’s Talent Acquisition Team will contact you to verify your experience, skill level, and interest in the role. During this call, expect behavioral questions and preliminary technical discussions.

Sometimes, the hiring manager may also join the call to answer your queries about the team and the overall role at Coupang. This initial screening usually takes about 30 minutes.

Technical Coding Test

If you pass the initial screening, you will be invited to complete a coding test. This is typically done using online platforms like HackerRank and will assess your problem-solving skills, coding proficiency, and familiarity with algorithms and data structures.

Technical Virtual Interview

Successfully navigating the coding test will lead to a technical virtual interview. This virtual stage, usually 1-1.5 hours long, involves solving algorithmic problems, often via platforms like HackerRank, and potential discussions on SQL queries or database management. You may be asked questions related to parsing intervals, tree traversal, and other common data engineering problems.

Depending on the role, additional areas such as system design, multithreading, and data structure efficiency may also be evaluated.

Onsite Interview Rounds

After clearing the virtual technical round, you’ll be invited for onsite interview rounds, which generally include:

1. Technical Rounds: These sessions will focus heavily on problem-solving, coding, system design, and technical knowledge. Typical formats include coding on a whiteboard, discussing system design, and explaining algorithms.
2. Behavioral Interviews: Discussion around your past experiences, challenges you faced, and how you embody Coupang’s core values.
3. Case Study/Business Questions: For senior roles, you might be asked to explain how you’d solve specific business problems or justify your approach to various scenarios.

Organizing these rounds can sometimes be inconsistent, so patience is key.

Final HR Interview

The concluding step is an HR interview, where you will discuss expectations, company culture, compensation, and any final questions you may have. This is also a great time to gauge if Coupang is the right fit for you.

Typically, interviews at Coupang vary by role and team, but commonly Data Engineer interviews follow a fairly standardized process across these question topics.

1. Write a function to find the nearest common ancestor of two nodes in a binary tree.

You are given a binary tree of unique positive numbers. Each node in the tree is implemented as a dictionary with the keys left and right, indicating the node’s left and right neighbors, respectively, and data that holds an integer value. Given two nodes as input (value1 and value2), write a function to return the value of the nearest node that is a parent to both nodes. If one of the nodes doesn’t exist in the tree, return -1.

2. Create a function to reconstruct the path of a trip from unordered flight tickets.

Consider a trip from one city to another that may contain many layovers. Given the list of flights out of order, each with a starting city and end city, write a function plan_trip to reconstruct the path of the trip so the trip tickets are in order.

3. Write a function to compute the minimum number of parking spots needed for buses.

Given a list of tuples, each containing two integers representing the arrival and departure time of buses, write a function minimum_parking_spots that computes the minimum number of parking spots needed to accommodate all the buses. The arrival and departure times are given in hours, ranging from 0 (12:00 AM) to 24 (11:59 PM). A bus only leaves on the next hour after its arrival.

4. Write a SQL query to calculate the 3-day weighted moving average of sales for each product.

The sales department is conducting a performance review and is interested in trends in product sales. Write a SQL query to calculate the 3-day weighted moving average of sales for each product. Use the weights 0.5 for the current day, 0.3 for the previous day, and 0.2 for the day before that. Only output the weighted moving average for dates that have two or more preceding dates.

5. How would you set up an A/B test for button color and position changes in a sign-up funnel?

A team wants to A/B test multiple changes in a sign-up funnel, such as changing a button from red to blue and/or moving it from the top to the bottom of the page. How would you set up this test?

6. How could you promote Instagram through Facebook?

You work on the growth team at Facebook and are tasked with promoting Instagram from within the Facebook app. Where and how could you promote Instagram through Facebook?

7. What metrics, graphs, or models would you use to analyze churn behavior for different pricing plans?

You work for a company like Netflix, which has two pricing plans: $15/month or $100/year. An executive wants you to analyze the churn behavior of users subscribed to either plan. What kinds of metrics, graphs, or models would you build to provide an overarching view of subscription performance?

8. What analysis would you run for an A/B test with non-normal distribution at Uber Fleet?

Uber Fleet has low data for experimentation, and you find that the distribution is not normal in an A/B test. What kind of analysis would you run, and how would you measure which variant won?

9. What retention rate is required to surpass revenue from a non-subscription price?

You sell an e-commerce product for $29 with a 50% per unit margin. You want to switch to a monthly subscription model at a 20% discount on the retail price. What retention rate would be required to surpass the revenue from the non-subscription price?

10. What metrics would you use to track the accuracy and validity of a spam classifier model?**

Assume you have built a V1 of a spam classifier for emails. What metrics would you use to evaluate its accuracy and validity?

11. When would you use a bagging algorithm versus a boosting algorithm?

Compare two machine learning algorithms. In which scenarios would you prefer a bagging algorithm over a boosting algorithm? Provide examples of the tradeoffs between the two.

12. What are the assumptions of linear regression?

List and explain the assumptions that must be met for linear regression to be valid.

13. How would you build a restaurant recommender on Facebook?

Describe how you would gather data and build a restaurant recommender system on Facebook. What are some potential downfalls or concerns with adding this feature?

14. How would you design the YouTube video recommendation algorithm?

Explain how you would design a recommendation system for YouTube videos. What important factors should be considered when building this algorithm?

15. How would you explain what a p-value is to someone who is not technical?

Explain the concept of a p-value in simple terms to a non-technical person, focusing on its role in determining the significance of results in hypothesis testing.

16. What could be the cause of the decrease in overall capital approval rates?

Analyze why the overall capital approval rate dropped from 85% to 82% despite individual product approval rates staying flat or increasing. Consider potential factors such as changes in the mix of products or external influences.

17. What is the probability that both flips result in the same side with one fair and one biased coin?

Calculate the probability that two flips of a randomly selected coin (one fair, one biased with ³⁄₄ heads) result in the same side.

18. What is the percentage chance a review is actually fake when the algorithm detects it as fake?

Given that 98% of reviews are legitimate and 2% are fake, and the algorithm’s accuracy rates, calculate the probability that a review is fake when identified as fake by the algorithm.

You should plan to brush up on any technical skills and try as many practice interview questions and mock interviews as possible. A few tips for acing your Coupang data engineer interview include:

• Technical Proficiency: Ensure you’re comfortable with data algorithms, multithreading, and SQL. Practice coding problems on platforms like HackerRank and LeetCode.
• Prepare for System Design: Be ready to design systems and databases, as this is a significant part of the interview process, particularly for senior roles.
• Understand Coupang’s Culture and Products: Be prepared to discuss how your own values align with Coupang’s mission and culture. Research their products and recent developments to add context to your answers.

What is the average salary for a Data Engineer at Barclays?

What skills are essential for a Data Engineer role at Coupang?

Key skills include expertise in data warehousing, ETL processes, and data architecture. Proficiency in tools and technologies like SQL, Python, AWS, Hadoop, Spark, Scala, and Kafka is highly desirable. Dimensional modeling and system design experience also play a significant role.

What is the working environment like at Coupang?

Coupang offers a hybrid working experience, blending the positives of onsite collaboration with the flexibility of working from home. The Whippany, NJ office provides state-of-the-art facilities like pool tables, cafes, and gyms to create a vibrant workplace.

What are the growth opportunities for a Data Engineer at Coupang?

Coupang, being a legacy institution in finance, provides ample opportunities for career growth, working on high-impact projects like regulatory reporting systems and market post-trade functions. Career development is supported through a structured approach involving cross-functional collaborations.

How does Coupang support work-life balance for Data Engineers?

Coupang is committed to offering flexible working arrangements. Discussions about specific work patterns can be had with the hiring manager. The company promotes a culture that balances professional and personal lives, aiding in a healthy work-life integration.

As financial services continue to dynamically evolve, Coupang is searching for proficient and innovative Data Engineers to join their ranks and contribute to their legacy of success and innovation. By honing your technical and behavioral expertise and leveraging the insights derived from previous interview experiences and job role expectations, you’ll be well-positioned to ace your interview.

If you want more insights about the company, check out our main Coupang Interview Guide, where we have covered many interview questions that could be asked. Additionally, explore our interview guides for other roles such as software engineer and data analyst to learn more about Coupang’s interview process for different positions.

Good luck with your interview!