Trustly Full Stack Engineer interview questions & guide 2026

Our interview process is designed to evaluate your technical depth, your problem-solving process, and how you align with our collaborative culture. The following questions represent the patterns we have observed in past interviews; use these to guide your preparation rather than as a definitive list.

Technical Implementation and Domain Knowledge

These questions focus on your ability to handle specific technical tasks and your understanding of web technologies. We are interested in your decision-making process when building tools from scratch.

• If you were tasked with building a web scraper, how would you approach it without using pre-built tools?
• What are the core challenges in maintaining high-performance API endpoints?

Preparation at Trustly should be holistic. You are expected to demonstrate technical mastery while showing that you can communicate your thought process clearly to both technical and non-technical stakeholders.

Technical Competency – This evaluates your proficiency in full-stack development, including backend API design and frontend considerations. You should be prepared to discuss your code in detail, justifying your architectural choices and explaining how you handle edge cases.

Analytical Thinking – We look for engineers who can deconstruct complex problems into manageable components. During your technical interviews, clearly articulate your steps, the trade-offs you considered, and your rationale for the final implementation.

Communication and Collaboration – Your ability to explain technical concepts to others is just as important as the code you write. Be ready to discuss your past projects, how you contribute to team success, and how you receive and implement constructive feedback.

Cultural Alignment – We value individuals who are proactive, respectful, and focused on the well-being of the team. Be prepared to share your professional motivations and how you contribute to a positive, inclusive, and productive work environment.

The interview process at Trustly is designed to be clear, professional, and thorough. We prioritize a humanized experience where you have the opportunity to engage with the team, understand our culture, and demonstrate your technical capability. You can expect a mix of technical assessments, behavioral interviews, and opportunities for you to ask questions about our business and engineering practices.

We value agility in our hiring process, but we do not compromise on the depth of our evaluation. You will likely interact with members of the technical team and HR, and you should be prepared for a process that examines both your hands-on coding skills and your ability to think strategically about software architecture.

This timeline provides a high-level view of the typical stages, ranging from initial screenings to technical evaluations and final discussions. Use this to pace your preparation, ensuring you have enough time to review your technical fundamentals and prepare thoughtful responses for the behavioral portions of the interview.

Technical Depth and Coding

We evaluate your ability to write clean, efficient, and well-documented code. We often use practical, real-world scenarios—such as building a web scraper—to see how you handle logic, data processing, and error handling without relying on external libraries.

Be ready to go over:

• Algorithm design – How you structure data and logic to solve specific constraints.
• System architecture – Understanding the flow of data between your API and the end-user.

As a Full Stack Engineer, you will own features from inception to deployment. You will be responsible for designing and implementing API endpoints that power our payment solutions, ensuring that every transaction is processed with high integrity. You will work closely with product managers to understand user needs and with other engineers to maintain a high bar for code quality.

Collaboration is central to this role. You will participate in code reviews, contribute to architectural discussions, and help refine our internal tools. We expect you to be a proactive team member who shares knowledge, helps troubleshoot issues across the stack, and contributes to the overall stability of our platform.

We look for engineers who are versatile and eager to learn. While technical skills are the foundation, we place equal importance on how you approach problems and work with others.

• Must-have skills:
  • Proficiency in modern backend and frontend frameworks.
  • Strong understanding of API design and implementation.
  • Ability to write clean, testable, and maintainable code.
  • Proven ability to debug complex systems independently.
• Nice-to-have skills:
  • Experience with data extraction techniques or web scraping.
  • Familiarity with cloud infrastructure and deployment pipelines.
  • Previous experience in the fintech or high-transaction-volume industries.

Q: How long does the interview process typically take? The timeline varies, but we strive for an agile and transparent process. From the initial screen to the final decision, we aim to keep you informed at every step.

Q: What is the most common reason candidates succeed? Successful candidates are those who not only write great code but also clearly communicate their thought process. We value engineers who can explain their trade-offs and are open to discussing how to improve their solutions.

Q: Is the technical test done live or independently? We typically use an independent technical assessment followed by a call to discuss your work. This allows you the space to demonstrate your skills in a practical, real-world context.

Q: What is the culture like at Trustly? We pride ourselves on a healthy, human-centric culture. We value professional well-being, clear communication, and collaborative problem-solving.

• Articulate your process: When solving technical problems, think out loud. We want to understand your logic, not just see the final result.
• Prepare your own questions: Use the interview to learn about our team culture and technical challenges. It shows you are serious about your potential fit.
• Be honest about trade-offs: There is no "perfect" code. If you made a shortcut, explain why and how you would fix it given more resources.
• Reflect on your past projects: Be ready to talk about the hardest problem you’ve solved and what you learned from it.

The Full Stack Engineer role at Trustly is an opportunity to build technology that powers the future of global payments. By focusing on your technical fundamentals, practicing clear communication of your design choices, and demonstrating a collaborative mindset, you will be well-positioned to succeed in our process.

We encourage you to use this guide to structure your preparation. For additional interview insights, practice questions, and comprehensive resources to help you prepare, explore the materials available on Dataford. You have the skills to succeed, and with focused preparation, you can confidently showcase your potential to our team.

The compensation data provided reflects market ranges for this role. Candidates should interpret these figures as a starting point for discussion, as total compensation packages typically include base salary, potential bonuses, and equity, adjusted for seniority and location.