6 Steps to Effectively Interview a Software Engineer

how to interview a software engineer

Interviewing software engineers is important for any company looking to form a strong and capable technical team. You must carefully plan and execute the interview process to ensure the candidate has the essential technical abilities and experience to succeed in the role. You will be testing not just the technical abilities of the applicant but soft skills like communication, conflict management, ability to bond with the team, and mental toughness as well. In this article, we will look at some key strategies for interviewing software engineers so that you can find the greatest talent for your team and ensure a successful and long-term hire.

1. Review the Role and Responsibilities

While interviewing software engineers, it is essential to clearly understand their expected position and job responsibilities. You need to be clear on the expectations from the candidate, along with what kind of projects and tasks they will be working on.

For instance, if you’re hiring for a front-end developer, then you will prepare your question set accordingly. Similarly, your questions will be entirely different for a data scientist position.

Regardless of the technology, you will still be asking a combination of technical, behavioral, and analytical questions to fully evaluate the candidate’s abilities.

2. Prepare a List of Technical Questions

Basic Programming Questions

When it comes to basic programming questions, you should ask about data types, control structures, functions, algorithms, error handling, and logging. They also should have strong knowledge of Git commands, debugging techniques, and testing methodologies. Some example questions are below:

  1. Give a practical example of using an array vs. a linked list.
  2. What features of object-oriented programming have you used in your projects?
  3. What is recursion, and how did you use it in your projects?
  4. What is polymorphism, and how did you use it in your projects?

Language-specific Questions

The language-specific questions may be related to syntax, data types, error handling, libraries, deployment, and so on. You should also ask about the latest version of the relevant programming language and what features are introduced in its latest version.  

System Design Questions

The candidate should have strong knowledge of system design concepts. You should ask questions about caching, load balancing, fault tolerance, high availability, security, data consistency, concurrency, and integrations.

Database Questions

Databases are an essential part of any software application. The database questions should be focusing on ACID, indexing, normalization, non-relational databases, ORM, data security, backup, deadlock, and query optimization.

DevOps Questions

The essential topics include containerization, managing secrets, infrastructure provisioning, continuous integration, continuous delivery, code branching, Git commands, and code merging. It is not necessary for software engineers to have hands-on experience in all areas; however, they should have good enough knowledge about all of these concepts.

3. Ask About the Candidate’s Past Projects and Experiences

In addition to technical questions, you should also ask the candidate about their previous projects and experiences. By knowing their past experience, you will be in a better position to evaluate whether the candidate is a good fit for this role or not. You will also get to know the technologies and business domains the candidate has experience with. 

For example, a developer who has always worked on a support project in a product-based company may not be able to work in a fast-paced project-based organization where a new product needs to be developed quickly. Similarly, if you are hiring for a healthcare company, you will prefer someone with experience in the healthcare domain.

 Some of the possible questions regarding the candidate’s past experience are as follows:

  1. What was the most challenging of your projects, and how did you handle the challenge?
  2. Give an example of a technically complex task that you were able to solve after a lot of effort.
  3. What steps do you take when you get stuck in a challenging code problem and there is no senior around to guide you?
  4. Walk us through the end-to-end development process of your last project.
  5. How do you handle the project requirements clarification process during an agile-based project?

4. Evaluate the Candidate’s Communication skills

The communication skills of a software engineer are one of the underrated factors during an interview. Regardless of how good a programmer is, it is a big drawback if he/she cannot explain technical concepts to a non-technical person. Software engineers often have to float different ideas, share their progress, defend a time estimate and provide feedback to managers. The absence of clear and frequent communication will make the job of a software engineer very difficult.

During the interview, you should closely watch the candidate’s body language, attitude, energy level, and communication skills. Some of the possible techniques to evaluate the communication skills of a software engineer are the following:

  1. Convene a roleplay exercise. For example, assume the candidate is asked to complete a 1-month project in 15 days without any additional developer and observe the candidate’s response to this scenario.
  2. Ask the candidate to justify the reason for choosing a particular strategy or technical component in any of the past projects.
  3. You should ask open-ended questions instead of Yes-No questions. That will encourage the candidate to speak more, and you will be better positioned to evaluate their communication skills. For example, you can ask, “Will artificial intelligence replace human beings in the future?”
  4. Keep an eye on the questions asked by the candidate. It is always a good sign when a candidate asks about the company and its culture. A candidate who does not ask any questions may seem uninterested in joining the company.

5. Offer a Coding Challenge or Take-home Project

Depending on the level of the position, you may want to give the candidate a coding challenge or take-home project to implement. This is especially important for technically challenging positions. 

The recruiting team can see the candidate’s problem-solving style and how they apply their technical skills to a real-world problem. The coding challenge will help you evaluate the applicant’s independence, time management skills, and technical strength to develop a high-quality project. You can also compare the code of different candidates implementing the same coding challenge; that will help you grade different candidates.

 When designing a coding challenge, you should take care of the following:

  1. The test should be relevant to the candidate’s skillset. Do not push the front-end candidate to code for back-end technology.
  2. Keep the time to complete reasonable, especially for an online coding challenge. Too long will make it boring and too short will not be helpful for good evaluation.
  3. The coding challenge should be clear. Proper instructions should be added to the challenge. You should also mention the criteria on which the candidate will be evaluated. For example, you may not give much importance to the system’s architecture for a junior developer, but for a senior position, you would give more weightage to the architecture and design of the project.
  4. Give good support to the candidate, especially during an online coding challenge. For example, the recruitment team should be available to answer any questions from the candidate, whether it is an online coding challenge or a take-home project.

Also, check out our article, which guides you on how to design a coding challenge along with the best coding challenges examples.

6. Consider the Fit with Your Team and Company Culture

Evaluating a candidate’s fit with the team and company culture is inevitable. You need to ensure that the candidate is aligned with your organization’s values and will be able to create a good bond with other team members. 

For example, if your company’s culture is very supportive and even senior managers provide a lot of support and guidance to junior team members, you will not hire a manager who likes to work in a silo and in an authoritative manner.

Some of the example questions to consider in this regard are the following:

  1. Ask behavioral questions to assess how the applicant handled various situations in the past. For example, you can enquire about any conflicts with a team member or boss, what the candidate did to address the conflict, and what the outcome was.
  2. You should ask questions about professional ethics, work style, and values. You should ascertain if the candidate likes to bond with the team and is people-friendly.
  3. Evaluate if the candidate is socially fit for your company not. You can ask a question like “Can you describe a time when you disagreed with a company policy? How did you convey your concern, and what was the result?”

Conclusion

Interviewing software engineers requires proper planning and careful execution to ensure that you select the right candidate for the job. In this article, we have suggested how you should conduct the interview for a software engineering candidate. We have also provided some examples and scenarios to elaborate on different questions for the interview. Note that each candidate is unique so you will need to approach the interview process with a high level of customization and adaptability to effectively assess the skills and possible fit for that particular role.