Sander Software Engineer interview questions & guide 2026

The following questions are representative of the patterns identified in recent interviews for the Software Engineer position. Use these to understand the scope of our technical and behavioral expectations.

Technical & Domain Expertise

These questions test your mastery of the languages and frameworks essential to our current projects.

• How do you handle memory management in Java applications?
• Describe your experience building scalable Python services within a medical or data-driven context.

Preparation for Sander requires more than just brushing up on syntax; it requires a mindset geared toward system reliability and collaborative problem-solving. Focus your preparation on these core evaluation criteria:

Role-Related Knowledge – You must demonstrate deep fluency in your primary language (e.g., Python, Java, or .NET). Interviewers will look for your ability to apply these tools to solve real-world industry problems rather than just recalling textbook definitions.

System Design & Scalability – We prioritize engineers who understand how their code interacts with larger infrastructure. Be prepared to discuss how your solutions handle load, security, and integration with existing systems.

Communication & Collaboration – Engineering at Sander is a team sport. Your ability to articulate your thought process clearly and work effectively with cross-functional partners is as important as the code you write.

The interview process at Sander is designed to evaluate both your technical depth and your ability to fit into a high-performing, collaborative culture. You can generally expect a structured progression that begins with an initial screening to gauge your technical background, followed by in-depth technical deep dives and behavioral assessments. Our goal is to understand how you tackle problems, how you learn, and how you contribute to team success.

The pace is rigorous but fair. We value candidates who show a methodical approach to problem-solving and who demonstrate a genuine interest in the specific challenges of our industry, such as medical innovation or infrastructure security.

The timeline above illustrates the progression from initial screening to final decision-making. Candidates should use this as a roadmap to manage their preparation, ensuring they are ready for deep-dive technical rounds after the initial assessment. Note that technical focus areas may shift slightly depending on whether you are interviewing for a Python, Java, or .NET specific role.

Technical Proficiency

We evaluate your ability to write clean, efficient, and secure code. Strong performance involves demonstrating not just "how" to code, but "why" you chose a specific implementation.

Be ready to go over:

• Language-specific best practices – Focus on the nuances of your preferred language.
• Testing methodologies – How you ensure your code is production-ready.
• Code reviews – Your ability to provide and receive constructive feedback.

Example scenarios:

• "Walk me through the most complex function you've written recently."
• "How do you handle dependency management in a large-scale project?"

System Design

This area tests your ability to visualize the "big picture." We look for engineers who can anticipate bottlenecks and design for longevity.

Be ready to go over:

• Infrastructure awareness – Understanding how your code runs on servers or in the cloud.
• Scalability patterns – How to handle increased traffic or data volume.
• Security considerations – Integrating security into the development lifecycle.

Example scenarios:

• "How would you architect a system to handle a 10x spike in traffic?"
• "Describe a time you had to refactor a legacy system to improve performance."

As a Software Engineer at Sander, your responsibilities will vary by team, but you will consistently be expected to bridge the gap between abstract requirements and working software. You will be responsible for the full development lifecycle, from initial design and prototyping to testing and deployment.

Collaboration is central to your role. You will work closely with product managers to define feature specifications and with operations teams to ensure your code integrates seamlessly into the production environment. Whether you are working on Innovation Médicale projects or managing Infrastructure, you will be a key contributor to the stability and evolution of our services.

A strong candidate for Sander is someone who combines technical discipline with a proactive, problem-solving mindset.

• Technical Skills – Proficiency in at least one of our core languages (Python, Java, or .NET) is non-negotiable. Experience with modern development tools and CI/CD pipelines is highly valued.
• Experience Level – While we hire across levels, we prioritize candidates who have successfully delivered projects in a professional or high-intensity environment.
• Soft Skills – You must be a clear communicator who can navigate complex stakeholder requirements and collaborate across teams.

Q: How long does the interview process typically take? The process usually spans 3 to 5 weeks from the initial screening to a final decision, depending on the complexity of the role and team availability.

Q: What is the most common reason candidates are not selected? The most frequent feedback relates to a lack of depth in system-level thinking or an inability to communicate the rationale behind technical decisions.

Q: Does Sander support remote work? Many of our roles are based in Brussels or Ghent, and while some flexibility exists, we value in-person collaboration for many of our infrastructure and innovation-focused teams.

Q: How much should I focus on algorithms vs. real-world application? At Sander, we favor real-world application. While you should be comfortable with standard data structures, we are more interested in how you build and maintain actual software systems.

• Focus on the "Why": Don't just show your code; explain the trade-offs you made.
• Be prepared for ambiguity: In many of our interviews, we present open-ended problems to see how you structure your thinking.
• Know the product: Take time to understand the specific domain you are applying for, whether it's Medical Innovation or Network Operations.
• Ask thoughtful questions: Your questions about our team culture and technical challenges are as important as your answers.

Preparing for a Software Engineer role at Sander requires a disciplined focus on both your technical craft and your ability to contribute to complex, high-impact systems. By understanding our core evaluation areas—technical depth, system design, and collaborative communication—you can significantly increase your confidence and performance during the interview process.

We encourage you to review your past projects, identify the specific technical challenges you overcame, and be ready to articulate your contributions with clarity and precision. You have the skills to excel here, and with the right preparation, you can demonstrate exactly why you are the right fit for the team. We look forward to seeing your technical expertise in action.