ING Mobile Engineer interview questions & guide 2026

The following questions are synthesized from real interview experiences at ING. While these illustrate common patterns, remember that your specific interview may vary based on the team’s current priorities and the seniority of the role.

Technical Proficiency (Android/iOS)

This category tests your core knowledge of the mobile stack, focusing on language-specific nuances and the platform SDKs.

• Explain the key differences between Kotlin and Java in the context of Android development.
• How do you manage memory leaks in a large-scale mobile application?

Preparation for ING requires a balanced approach. You should not only be technically sharp but also ready to articulate your design decisions and demonstrate a collaborative mindset.

Role-related knowledge – You must be comfortable discussing the technical stack you use daily. Expect to be challenged on why you choose specific libraries or design patterns over others.

Problem-solving ability – Interviewers are looking for how you approach ambiguity. If a question seems unclear, do not hesitate to ask for clarification; demonstrating your thought process is often more important than the final answer.

Culture fit and collaboration – ING emphasizes teamwork. Be prepared to discuss how you contribute to a positive team environment and how you handle conflict, as these are as vital as your coding skills.

The interview process at ING is typically structured to assess both your technical capabilities and your potential as a team member. You can expect an initial screening call with an HR representative, followed by one or more technical assessments. These may include a take-home assignment or a live coding session with engineers from the team. The final stages usually involve behavioral interviews with team or chapter leads to ensure cultural alignment.

This timeline provides a high-level view of the progression from initial contact to the final decision. Use this to pace your preparation, focusing on technical fundamentals early on and shifting toward behavioral narratives as you reach the final stages. Note that processes can vary by location and team size, so always confirm the next steps with your recruiter.

Technical Depth

ING interviewers look for engineers who understand the "why" behind their code, not just the "how." A strong candidate demonstrates mastery of their primary language and understands the underlying platform mechanics.

Be ready to go over:

• Dependency Injection – How it facilitates testing and modularity.
• Testing Strategies – Why unit testing and UI testing are non-negotiable.

As a Mobile Engineer at ING, you will primarily focus on developing high-quality features that enhance the customer banking experience. Your day-to-day will involve writing clean, maintainable code, participating in code reviews, and contributing to architectural discussions. You are expected to be an advocate for quality, which includes writing robust unit tests and ensuring that the app remains performant as it grows.

Collaboration is central to this role. You will work closely with other engineers to refine the technical roadmap and communicate progress to product owners. You may also be involved in mentoring junior developers and participating in "chapter" meetings, where you share best practices and help set technical standards for the wider mobile organization.

To be competitive, you should possess a solid foundation in mobile engineering and a proactive attitude toward learning.

• Must-have skills: Proficient in Kotlin (for Android) or Swift (for iOS), strong experience with mobile architecture patterns, and a proven track record of writing testable code.
• Nice-to-have skills: Experience with CI/CD pipelines, familiarity with reactive programming, and a background in financial services or high-security applications.

Q: How long should I prepare for the technical interviews? A: Depending on your current experience, 2–4 weeks of focused practice on data structures, system design, and your specific mobile platform should suffice.

Q: Will I receive feedback if I am not selected? A: While some candidates report receiving helpful feedback, others have noted a lack of communication. Always ask your recruiter for feedback at the end of each stage.

Q: Is the technical assignment difficult? A: Most candidates find the homework assignments to be of reasonable difficulty. Focus on writing clean, well-tested code rather than over-engineering the solution.

• Prioritize Testing: ING values robust, testable code. Always explain your testing strategy during technical discussions.
• Clarify Requirements: If a question seems poorly phrased or vague, ask for specific examples or constraints before starting.
• Be Professional: Even if an interviewer seems apathetic or aggressive, maintain your composure and focus on demonstrating your expertise.
• Prepare for Behavioral Questions: Use the STAR method (Situation, Task, Action, Result) to structure your answers to behavioral questions.

A career as a Mobile Engineer at ING offers the chance to work on high-impact products at a significant scale. By focusing on your technical fundamentals, being prepared to discuss your architectural choices, and maintaining a collaborative mindset, you will position yourself as a strong candidate.

Remember that every interview is an opportunity to learn. Regardless of the outcome, reflect on the questions asked and how you responded to improve for your next challenge. You have the skills to succeed; stay focused, prepare thoroughly, and approach your interviews with confidence.