The Tech Interview Behind the Scenes: Krasimir Kostadinov

The Tech Interview Behind the Scenes is an HRLabs series.
Let’s take a look behind the scenes of the technical interview process from the interviewers' perspective.
Our goal is to provide candidates with valuable tips and recommendations directly from professionals who conduct interviews for various technical roles.

“Trust starts building from the interview.” shares Krasimir Kostadinov, Chief Technology Officer at Scalefocus.

Tell us more about your career path.

It's a bit of a cliché and may be discouraging for those changing careers, but ever since I got my first computer – the Pravetz 8C, where I would play around and write simple code in Basic – I’ve always wanted to work in IT.

I’ve been programming non-professionally since 1994 and professionally since 2004. Until 2012, I worked as a freelance developer for companies in Bulgaria and Germany.

Since 2016, I've held various management positions, leading teams and developing strategic goals.

As a candidate, have you had any strange interviews? What about interviews that impressed you?

I've had some memorable experiences as a candidate.

For instance, I once had an interview in an apartment where the rooms were clearly not set up for work (it was obvious people were living there), yet there were more than 10 people working in that space.

What skills and qualities do you look for in a candidate? How can a candidate stand out during the interview?

A spark in the eyes regarding the topics we discuss, competence, and honesty—there’s no way to work with someone you can’t trust, and that trust begins to build during the interview.

To me, a significant ego (often seen in more experienced people, though not exclusively) is a red flag, as the moment you believe you know everything, you stop learning and developing—like the parable of the teacup: a cup filled with ego leaves no room for new knowledge.

I’m impressed by candidates who bring those “aha” moments and teach me new things, offering elegant or fresh solutions to problems I hadn’t considered.

What questions do you typically ask in technical interviews? Do you have specific tasks or problems that you often use to assess candidates?

I’m guided by the candidate’s previous experience. I’m interested in how they view their work, what they’re proud of, and what they’ve learned from their experiences—for me, this gives a solid insight into their motivation, temperament, and professional outlook.

Naturally, we also dive into technical topics.

How important are good communication skills for a candidate? How do they impact the overall interview?

If you lack communication skills but have a genius-level talent in a given field (top 2 percent of the normal distribution), you may become a misunderstood virtuoso or an academic. 

However, if you have strong communication skills and aren't a genius but are willing to work hard—you can become anything you set your mind to.

How important is cultural fit when making a hiring decision? How do you assess whether a candidate will fit well into the team?

The culture of an organization or team is one of its strongest assets or potential obstacles, depending on the context.

It’s not easy to build, nor is it easy to replicate—many try to adopt processes from successful companies, but if they conflict with existing culture, they fail.

The often-repeated phrase that culture “eats process for breakfast” rings very true.

A well-aligned culture and cultural compatibility between individuals and organizations/teams are foundational to success in most endeavors.

Culture can be evaluated through specific questions about previous team experiences, interview behavior, topics the candidate feels emotional about, and much more.

In certain cases, it’s also helpful to invite a current team member from the specific team being interviewed for to assess the candidate firsthand.

I remember being invited to lunch with teams for which I was interviewed years ago—an excellent way to evaluate fit.

What are the most common mistakes candidates make during an interview? What advice would you give candidates on how to prepare for an interview?

Often, candidates approach the interview as a test and try to achieve the highest score possible.

However, the interview process is about mutual fit between the candidate and the manager, team, company.

While ambition is valuable, it can be misleading in a technical interview.

Many candidates dive deeply into specific technologies without understanding the fundamental concepts that underpin them (e.g., Hibernate/JPA/EclipseLink/EF vs. ORM). Similarly, candidates who get overly creative with fine-tunned CVs aren’t doing themselves any favors.

What advice would you give to candidates who want to improve their technical skills? Are there any resources you would recommend?

Try to thoroughly understand the concepts that underpin certain technologies and learning new technologies will become far easier.

Technologies constantly evolve, but the fundamental concepts in IT have been around for decades—many are even over half a century old.

Share more about the best (or worst) interviews you've conducted.

The worst interview I conducted was with a candidate who was extremely motivated and eager to impress. 

She encountered difficulties with a simple task and refused to switch to a different one. 

After putting in some effort to solve it, she began to cry, and we had to take a break before moving on to another task. She eventually sent her solution for the first task afterward.

How do you evaluate a candidate during an interview—based solely on their theoretical knowledge, or is their approach to solving a problem/task more important to you? What other factors do you consider when making a decision?

Knowledge (utilizing existing solutions) and the ability to approach a task correctly are equally important.

For me, the most crucial aspect is gathering additional information or understanding constraints when solving a problem, as well as thinking through the problem carefully before jumping into the first solution that comes to mind.

What would you like candidates to know about the interview process in your company? What could be helpful for them in their preparation?

Understand the concepts behind the technologies you use.

Share a funny story from your experience as an interviewer :)

I once had a candidate many years ago who was brought to the interview by his mother, who waited at the reception while he finished the interview! :)