Data Engineer Technical Interview Questions & Answers

April 7, 2021

Data Engineer Technical Interview Questions and Answers

The world operates on large amounts of data and emerging tech trends. To keep up with this demand, you’ll want to hire a data engineer that understands all the technical nuances of the job. They should possess specialized skill sets ranging from data pipeline maintenance, developing algorithms, and infrastructure redesign to other in-demand skills. Additionally, they should have a firm grasp of business and client needs, how to optimize data, and how to communicate with stakeholders. As such, utilizing data engineer interview questions to quiz your candidates is an excellent way to determine if they possess those skills.

According to AltexSoft, a data engineer is “an engineering role within a data science team or any data-related project.” As such, this individual would essentially be responsible for executing and managing all complex technical elements of data infrastructure. 

How To Pre-Screen a Data Engineer

The role of a Data Engineer requires more than just a general knowledge of complex data, computer science, and engineering. For instance, it also involves an understanding of the mechanisms behind successfully deploying and testing databases. This requires proficiency in SQL database design and other technical skills. Finding candidates that can deliver results and meet all of the skill sets and criteria for the role can be challenging. As a result, it’s important to align yourself with a specialized recruiting firm that can do the heavy lifting, pre-screening, and recruiting process for you. 

Why Pre-screen Candidates? 

It’s crucial to pre-screen tech candidates before hiring them. This allows you to assess whether they are the right fit for the role you’re looking to fill. Focus Global Tech Solutions pre-screens applicants for you, saving you the time and hassle of sifting through hundreds of unqualified or “fake” candidates. In other words, we’ll ensure that the candidates you receive are relevant to the actual job position and capable of performing their day-to-day duties at a high level.

Whether you’re partnering with a specialized staffing firm, or handling it solo, fear not – the Focus GTS team has compiled a list of key skills and questions that are typically asked during the recruiting and screening process. These questions are a great place to start, particularly when you’re unsure of how to vet your candidates!

What Are the Key Skills of a Data Engineer?

Data Engineers are in-demand and responsible for analyzing data platforms and integration tools. Some of the most common technical skills required of a data engineer include expertise in multiple complex programming languages (including proficiency in SQL and AWS), and in other emerging technologies. Aside from programming languages, they also must be savvy in the realm of statistical modeling, building and deploying data pipelines, and should have a solid foundation when it comes to software engineering and data analysis. 

Typically, the average salary of a data engineer can vary from state to state. On average, data engineers in the United States can make up to an average annual salary of $127,983, according to Springboard. Springboard also lists the top technical skill sets that hiring managers look for when hiring for data engineers, which include the following: SQL and NoSQL, data warehousing solutions, ETL tools, machine learning, Data APIs, programming languages, algorithms and data structures, and more. In addition to technical skills, the candidate must also possess a good mix of collaborative and communicative skills as well.

Sample Pre-Screen Questions To Ask a  Data Engineer 

We asked one of our Fortune 100 clients for a few sample interview questions that are typically asked during a pre-screen interview for a data engineer role. Here’s a sneak peek: 

1. True/False. In Apache Spark, RDD and DataFrame are the same.

  • False

2. Follow-up question:  The Spark data frame is built on RDDs.

  • True

3. What does Spark RDD stand for?

  • Resilient Distributed Dataset

4. True/False. In Python, the list data structure can be used to emulate Stack and Queue Data Structure.

  • True

5. In SQL, describe different types of table joints.

  • Inner Join, Left Join, Right Join, Full Join, (Self Join – optional)

6. Which of the following are managed services in AWS? Choose from: EC2, Lambda and Step Function.

  • Lambdas and Step Function


Align yourself with an expert at Focus GTS. If you’re thinking of partnering with us and would like to have us take over the recruiting process to save you time and money, give us a call!