Back-End Software Engineer: Must-Ask Interview Questions

Prepping to interview a candidate for your Back-End Software Engineer position, but unsure of what questions to ask to ensure you’re finding someone who can bring that “extra something” to your company? We’ve got what you need. Use these sample questions to help you determine which candidate is more than merely skilled and experienced in the basics—someone who will bring the acumen that can help elevate your company and support its needs above and beyond the usual. Not only will that help make the interview process easier, it will also help you uncover the tech professionals who are deep-thinkers, high-performers, and all-around true standouts.


Interviewing another position? Check out Dice’s library of interview questions.


Question: What programming languages do you prefer to work with?

Why you should ask: There are a lot of moving parts to this position, but one of the most important capabilities your Back-End Software Engineer should have is in coding. By asking your candidate this question, you’re not only offering them a nice warm-up before you get to tougher asks, you’re also getting a window into their capabilities, preferences, and deeper understanding of how they’ll meet the requirements associated with this position. You’ll know if they’re a proficient and efficient coder based on how they answer this question.

An answer you’d hear from a stand-out candidate: “I think it’s important for me to be as familiar as I can be with all the relevant programming languages, as different projects and applications can benefit from different approaches to coding and the programming languages that support them. However, given the choice, my preference is to work with PHP, Java, Ruby and Python. I find they offer me the most versatility and capability across the widest swath of projects, so they wind up being my go-to languages depending on what the ask is, and what the end result is that we’re looking to achieve. Sometimes Ruby is more suited to one aspect of a project than Python, or PHP is a stronger language to use for certain aspects of an application above all others, but that’s why I like to work across multiple languages, so that if I can’t accomplish something I want to accomplish with one of them, I can pivot to another and create what the client or company is looking for.”


Question: What is your approach to debugging and improving applications and programs?

Why you should ask: One of the most important parts of the development lifecycle is the troubleshooting and debugging phase. Similarly, when a company has multiple offerings under their belt, they’re always looking for ways to improve their current offerings to stay competitive and maintain their user base. Asking this question helps you gain more insight into your Back-End Software Engineer candidate’s troubleshooting process, and gauges how they’ll handle it if you ask them to take on the task up updating and upgrading existing applications and programs.

An answer you’d hear from a stand-out candidate: “In terms of debugging, I’m pretty meticulous about my testing process. I use a debugging tool that goes through all of my code and helps me see where the issues are, if any. From there, I work to determine how to fix any of the issues that came up in the debugging process, and how to implement those fixes or changes in a way that doesn’t affect supporting code throughout the project. As for working with existing applications or programs, I like to get a clear view of what currently works with the project before I start working with it, so I know what people like about it. From there, I can learn more about what they feel needs improving, and then craft a plan to move forward that uses the best of what currently works, and then build upon what doesn’t work in a way that addresses the company or client’s needs, and what they ultimately want the user to experience.”


Question: What has been your most challenging team project, and how did you work through it?

Why you should ask: People throw around the term “team player” a lot, but they don’t really know how to ask about it and determine whether or not someone really is a team player. This is a good way to determine whether or not your Back-End Software Engineer candidate has what it takes to work across multiple departments—and in some cases, collaborate with management or directly with clients—to successfully shepherd a project from conception to completion in conjunction with the entire team.

An answer you’d hear from a stand-out candidate: “There was one project I had with the last company I was at where we’d planned out every step through every department, and despite that, it felt like everything that could go wrong, did. Throughout the development lifecycle I worked in conjunction with the front-end developers, designers, and system administrators at different points to work through the troubleshooting process and brainstorm solves for the issues we were facing. We had to revise our estimates and change course a few times, which was to be expected a bit given that what we were looking to create was pretty ambitious. And yes, there were some late nights—and some sleepless ones. In some instances we were able to circumvent issues before they became problems, in others we had to work them through as they presented themselves, but in the end, the team came together to support one another and we were able to celebrate a successful launch.”


Question: What is your approach to coding and ensuring your code is solid, organized and optimized?

Why you should ask: Think of this question as an extension of the first one you asked about programming language preferences. Knowing the languages is one thing, but you want a candidate who lives, eats and breathes code. Part of this means your Back-End Software Engineer candidate should know how to manage their own code, recognize errors when they come up, know how to work through them, but they should also know best practices for maintaining their code.

An answer you’d hear from a stand-out candidate: “I spend most of my time writing code, as that’s largely what’s necessary for me to effectively fill the role of a Back-end Software Engineer, but I also spend time managing UI tests, optimizing and debugging as needed. I tend to rely on OOP to organize my code, however in the past I’ve also used procedural programming to classify my code by action instead of object. But again, it comes down to what’s most efficient and required based on whatever project I’m working on. It also depends on what the team preference is, as I find some are particular about how it’s organized. But on the whole, I’m constantly testing and re-testing my code to ensure it meets the project’s needs, and I work to maintain my skills outside of the office to ensure I’m always up to date and working at peak capacity.”


Question: What are some of the best practices you employ during the development lifecycle?

Why you should ask: Approaches to development lifecycles can differ from company to company, and even client to client. But while certain aspects are flexible, others remain standard across the board—and it’s there that your Back-End Software Engineer candidate will show you their know-how and capability to handle the pressures associated with seeing a project through to completion by using the methodologies that are known to produce results. Bonus points if they can talk about specific processes that help them achieve goals and milestones.

An answer you’d hear from a stand-out candidate: “Overall, the projects I’ve worked on mostly follow the Agile approach, which is where my affinity for testing and retesting code comes from. However, I do have experience using the more progressional approach of the Waterfall method. I find that having experience in both makes it easier for me to transition between teams, particularly during the troubleshooting process, but I’m happy to work in either methodology depending on what’s required to complete the project. I also have experience working in unit testing and find it to be an important part of the process for finding logic errors and coding flaws. I also use multi-threading to improve application performance, rely on MVC to separate code, and use Hibernate for ORM frameworks.”