Fiserv Software Engineer Interview Questions + Guide in 2025

Fiserv is a global leader in Fintech and payments, dedicated to moving money and information securely and reliably across the globe.

As a Software Engineer at Fiserv, you will be integral to the development of mission-critical applications that support payment processing for numerous financial institutions and merchants. Your responsibilities will include designing, developing, and testing server-side applications primarily using Java or C on platforms like HPE NonStop, ensuring high availability and performance. You will collaborate closely with cross-functional teams to deliver robust features while adhering to best practices in software engineering. Strong proficiency in online transaction processing (OLTP) applications, cloud technologies, and modern development practices such as CI/CD will be essential for success. Furthermore, your ability to communicate effectively with stakeholders and participate in code reviews will greatly contribute to maintaining a high-quality standard across projects.

This guide will provide you with insights into the skills and knowledge needed for the role, along with focused interview preparation strategies to help you stand out in the competitive hiring process at Fiserv.

The interview process for a Software Engineer at Fiserv is structured and typically involves multiple rounds, focusing on both technical and behavioral aspects to assess candidates thoroughly.

1. Initial Screening

The process begins with an initial screening, which may be conducted via a phone call or video conference. During this stage, a recruiter will discuss your background, the role, and the company culture. This is also an opportunity for you to ask questions about the position and the team dynamics.

2. Technical Assessment

Following the initial screening, candidates usually undergo a technical assessment. This may include a written test that evaluates your coding skills, data structures, and algorithms. The assessment often consists of multiple-choice questions and coding challenges that require you to demonstrate your proficiency in programming languages relevant to the role, such as C, Java, or Python.

3. Technical Interviews

Candidates who pass the technical assessment will typically participate in one or more technical interviews. These interviews are conducted by senior engineers or technical leads and focus on your problem-solving abilities, coding skills, and understanding of software engineering principles. You may be asked to solve coding problems in real-time, discuss your previous projects, and explain your thought process while coding.

4. Managerial Round

After the technical interviews, candidates may have a managerial round. This interview assesses your fit within the team and the organization. Expect questions about your work style, how you handle challenges, and your approach to collaboration. This round may also include discussions about your career goals and how they align with Fiserv's objectives.

5. HR Interview

The final stage of the interview process is typically an HR interview. This round focuses on your overall fit for the company culture and may cover topics such as your salary expectations, benefits, and any logistical questions regarding the role. The HR representative will also discuss the next steps in the hiring process.

Throughout the interview process, it is essential to demonstrate not only your technical expertise but also your ability to communicate effectively and work collaboratively within a team.

Now, let's delve into the specific interview questions that candidates have encountered during their interviews at Fiserv.

Here are some tips to help you excel in your interview.

Understand the Technical Landscape

Given the emphasis on specific technologies like C, TAL, and the HP NonStop platform, ensure you have a solid grasp of these areas. Review the fundamentals of online transaction processing (OLTP) applications and familiarize yourself with the unique aspects of the NonStop architecture. Be prepared to discuss your experience with these technologies in detail, as interviewers will likely probe your understanding of how they apply to real-world scenarios.

Prepare for a Multi-Round Interview Process

The interview process at Fiserv can involve multiple rounds, including technical assessments, HR interviews, and possibly managerial discussions. Be ready to articulate your experiences clearly and concisely across different rounds. Practice explaining your past projects and how they relate to the role you are applying for, as this will help you maintain consistency and confidence throughout the process.

Showcase Problem-Solving Skills

As a software engineer, your ability to solve complex problems is crucial. Expect to encounter scenario-based questions that assess your critical thinking and problem-solving skills. Prepare to discuss specific challenges you've faced in previous roles and how you approached them. Use the STAR (Situation, Task, Action, Result) method to structure your responses effectively.

Emphasize Collaboration and Communication

Given the collaborative nature of the role, highlight your experience working in cross-functional teams. Be prepared to discuss how you have partnered with product managers, designers, and other engineers to deliver successful projects. Strong communication skills are essential, especially when explaining technical concepts to non-technical stakeholders, so practice articulating your thoughts clearly.

Familiarize Yourself with Fiserv's Culture

Fiserv values innovation, diversity, and inclusion. Research the company's mission and values, and think about how your personal values align with theirs. Be ready to discuss how you can contribute to fostering a positive and inclusive work environment. This alignment can set you apart from other candidates.

Prepare for Behavioral Questions

Expect behavioral questions that explore your past experiences and how they relate to the role. Questions may include scenarios about teamwork, conflict resolution, and adaptability. Reflect on your career journey and prepare anecdotes that demonstrate your skills and growth as a software engineer.

Practice Coding and Technical Assessments

Given the technical nature of the role, you may be asked to complete coding challenges or technical assessments. Brush up on your coding skills, particularly in C and SQL, and practice common algorithms and data structures. Use platforms like LeetCode or HackerRank to simulate coding interviews and improve your problem-solving speed.

Be Ready for Questions About the Future

Interviewers may ask about your career aspirations and how you see yourself growing within the company. Prepare thoughtful responses that reflect your long-term goals and how they align with Fiserv's direction. This shows your commitment to the role and the organization.

Follow Up with Gratitude

After the interview, send a thank-you email to express your appreciation for the opportunity to interview. This not only reinforces your interest in the position but also leaves a positive impression on your interviewers.

By following these tips and preparing thoroughly, you can approach your interview at Fiserv with confidence and clarity, increasing your chances of success. Good luck!

In this section, we’ll review the various interview questions that might be asked during a Software Engineer interview at Fiserv. The interview process will likely focus on your technical skills, problem-solving abilities, and understanding of software development principles, particularly in the context of payment processing and online transaction systems. Be prepared to demonstrate your knowledge of programming languages, data structures, algorithms, and system design.

Technical Skills

1. Can you explain the concept of Object-Oriented Programming (OOP) and its main principles?

Understanding OOP is crucial for software development, especially in languages like Java and C.

How to Answer

Discuss the four main principles: encapsulation, inheritance, polymorphism, and abstraction. Provide examples of how you have applied these principles in your projects.

Example

“OOP is a programming paradigm based on the concept of objects, which can contain data and code. The four main principles are encapsulation, which restricts access to certain components; inheritance, which allows a class to inherit properties from another; polymorphism, which enables methods to do different things based on the object; and abstraction, which simplifies complex reality by modeling classes based on the essential properties.”

2. Describe your experience with SQL and how you have used it in your projects.

SQL is essential for managing and querying databases, especially in payment processing systems.

How to Answer

Highlight your experience with SQL queries, database design, and any specific projects where you utilized SQL effectively.

Example

“I have extensive experience with SQL, particularly in designing and querying relational databases. In my last project, I optimized complex queries to improve performance, which reduced the data retrieval time by 30%. I also implemented stored procedures to automate repetitive tasks, enhancing the overall efficiency of the database operations.”

3. What is the difference between a stack and a queue?

Understanding data structures is fundamental for efficient algorithm design.

How to Answer

Explain the characteristics of both data structures and provide examples of their use cases.

Example

“A stack is a Last In First Out (LIFO) structure, where the last element added is the first to be removed, like a stack of plates. A queue, on the other hand, is a First In First Out (FIFO) structure, where the first element added is the first to be removed, similar to a line of people waiting. I used a stack for backtracking algorithms and a queue for breadth-first search in graph traversal.”

4. Can you explain the concept of RESTful APIs and how you have implemented them?

APIs are crucial for enabling communication between different software systems.

How to Answer

Discuss the principles of REST and your experience in designing and implementing RESTful services.

Example

“RESTful APIs are based on representational state transfer principles, which use standard HTTP methods like GET, POST, PUT, and DELETE. I implemented a RESTful API for a payment processing system that allowed clients to securely initiate transactions and retrieve transaction statuses. I ensured that the API was stateless and used JSON for data interchange.”

5. What is your approach to debugging and troubleshooting code?

Debugging skills are essential for any software engineer.

How to Answer

Describe your systematic approach to identifying and fixing bugs in your code.

Example

“My approach to debugging involves first reproducing the issue to understand its context. I then use logging to gather more information about the state of the application at the time of the error. After identifying the root cause, I implement a fix and run tests to ensure that the issue is resolved without introducing new bugs.”

System Design

1. How would you design a payment processing system?

This question assesses your ability to design scalable and reliable systems.

How to Answer

Outline the key components of the system, including architecture, data flow, and security considerations.

Example

“I would design a payment processing system with a microservices architecture to ensure scalability and maintainability. Key components would include a user authentication service, a transaction service for processing payments, and a notification service for sending updates to users. I would implement security measures such as encryption for sensitive data and use tokenization to protect payment information.”

2. Describe a challenging technical problem you faced and how you solved it.

This question evaluates your problem-solving skills and resilience.

How to Answer

Provide a specific example, detailing the problem, your approach, and the outcome.

Example

“In a previous project, we faced performance issues with our transaction processing system during peak loads. I analyzed the bottlenecks and identified that our database queries were inefficient. I optimized the queries and implemented caching strategies, which improved the system's throughput by 50% during peak times.”

3. What strategies do you use for ensuring code quality?

Code quality is vital for maintainability and reliability.

How to Answer

Discuss your practices for writing clean, maintainable code and conducting code reviews.

Example

“I ensure code quality by adhering to coding standards and best practices, such as writing clear and concise code, using meaningful variable names, and adding comments where necessary. I also advocate for regular code reviews within the team, which not only helps catch potential issues early but also fosters knowledge sharing among team members.”

4. How do you stay updated with the latest technologies and trends in software development?

Continuous learning is essential in the tech industry.

How to Answer

Share your methods for keeping your skills current, such as online courses, reading, or attending conferences.

Example

“I stay updated by following industry blogs, participating in online courses, and attending tech meetups and conferences. I also contribute to open-source projects, which allows me to learn from others and apply new technologies in real-world scenarios.”

5. Can you explain the importance of CI/CD in software development?

Understanding CI/CD is crucial for modern software engineering practices.

How to Answer

Discuss the benefits of continuous integration and continuous deployment in the software development lifecycle.

Example

“CI/CD is essential for automating the software delivery process, allowing teams to release code more frequently and reliably. Continuous integration ensures that code changes are automatically tested and merged into the main branch, reducing integration issues. Continuous deployment automates the release process, enabling faster delivery of features and bug fixes to users, which ultimately enhances customer satisfaction.”