A Software Engineer at Zelis Healthcare plays a critical role in transforming the healthcare financial ecosystem. By designing, developing, and optimizing high-throughput transaction engines, payment gateways, and claim-routing platforms, you directly impact how payers, providers, and consumers interact. The work here sits at the high-stakes intersection of fintech and healthcare IT, requiring systems that are not only highly performant but also compliant with strict healthcare regulations like HIPAA.

Your contributions will directly influence the efficiency of medical billing and payments across the United States. Whether you are optimizing SQL databases, scaling backend services in .NET/C#, or managing enterprise data warehouses with Snowflake, your engineering decisions will reduce administrative friction and lower healthcare costs. This is an environment where code quality, system resilience, and data security are paramount, making it an exceptionally rewarding space for engineers who thrive on solving complex, real-world problems.

To succeed in the Zelis Healthcare interview process, you must be prepared for a mix of deep technical assessments, architectural discussions, and behavioral evaluations. The questions asked are highly reflective of the company's tech stack and operational challenges. The following categories represent the patterns observed in real interview experiences.

C# and Object-Oriented Programming (OOP)

As a primary backend language at Zelis Healthcare, C# is evaluated thoroughly. Interviewers will test your understanding of language fundamentals, design patterns, and how to apply OOP principles to real-world scenarios.

• Explain the difference between interface inheritance and class inheritance in C#, and provide a scenario where you would choose one over the other.
• How do you implement encapsulation to protect sensitive payment data within a transaction processing service?

Preparing for an interview at Zelis Healthcare requires a balanced approach. You must demonstrate deep technical expertise while showing that you can collaborate effectively in a highly regulated corporate environment.

Technical Depth in the Core Stack – You must have a strong command of C#, .NET, and relational databases. Expect to write code on a whiteboard, in an IDE, or explain your past implementations in granular detail.

Real-World Problem Solving – Avoid memorizing generic algorithms. Focus on how to apply software engineering principles to real-time scenarios, such as designing APIs, processing batch files, or creating robust unit tests.

Quality-First Mindset – Zelis Healthcare deals with financial transactions, meaning bugs can have major financial consequences. You will be evaluated on your ability to write clean, maintainable, and thoroughly tested code.

Adaptability and Communication – You must be able to explain complex technical designs to both technical architects and non-technical business stakeholders clearly and confidently.

The interview process for a Software Engineer at Zelis Healthcare typically spans three to four stages. It is designed to evaluate your technical capabilities, architectural thinking, and cultural alignment. Depending on the location and seniority of the role, the process may move quickly or involve multiple steps over a few weeks.

In the United States, the process often begins with a recruiter screen, followed by a technical discussion with the hiring manager, and concludes with a deep-dive interview with system architects. In global offices like Hyderabad, candidates often undergo a technical assessment or online MCQ test, followed by two in-depth technical discussion rounds (which may be scheduled on weekends), a managerial round, and a final HR discussion.

The visual timeline above outlines the typical progression of stages from your initial application to the final offer. Use this structure to pace your preparation, ensuring you allocate enough time to practice live coding, system design, and behavioral frameworks. While the exact timeline can vary by team and location, most candidates complete the journey within three to four weeks.

To stand out during the selection process, you must understand the core competencies that Zelis Healthcare interviewers target.

C# Fundamentals & OOP Implementation

This evaluation area goes beyond basic syntax. Interviewers want to see that you understand how to write efficient, object-oriented code that is modular and easy to extend.

Be ready to go over:

• OOP Concepts in Action – Implementing inheritance, polymorphism, encapsulation, and abstraction to solve practical engineering challenges.
• Memory Management – How the .NET Garbage Collector works and how to write memory-efficient code using structures, classes, and proper resource disposal.
• Asynchronous Programming – Leveraging async/await patterns in C# to build non-blocking, high-performance APIs.
• Advanced concepts (less common) – Generics, LINQ performance optimization, and custom middleware development in .NET Core.

Example scenarios:

• "Design a payment processing library that supports multiple payment methods (Credit Card, ACH, Check) using OOP principles."
• "Refactor a tightly coupled codebase to utilize dependency injection and interface-based programming."

Real-Time Scenario Implementation & Unit Testing

At Zelis Healthcare, writing code is only half the battle; you must also prove that it works reliably. You will be asked to implement real-time scenarios and write corresponding unit tests.

Be ready to go over:

• Scenario-Based Coding – Implementing business logic on the fly based on a set of evolving requirements.
• Realistic Unit Testing – Creating unit tests that use realistic input scenarios and mock dependencies, rather than relying on trivial dummy data.
• Test-Driven Development (TDD) – Demonstrating how writing tests first can guide your software design.

Example scenarios:

• "Write a function to validate and parse a healthcare claim file, and then write unit tests that handle edge cases like missing fields and malformed dates."
• "Implement a retry mechanism for an external API call and write tests to simulate network failures and timeouts."

Database Design & SQL Optimization

Because Zelis Healthcare handles massive datasets, your ability to design scalable databases and write optimized queries is crucial.

Be ready to go over:

• Schema Design – Designing normalized database schemas that prevent data redundancy while maintaining high read/write performance.
• Query Optimization – Analyzing execution plans, identifying bottlenecks, and optimizing complex SQL queries.
• Data Warehousing – Understanding how to structure data for analytical workloads, particularly if you are interviewing for roles involving Snowflake or large-scale data processing.

Example scenarios:

• "Optimize a query that takes several minutes to run across tables with millions of records."
• "Design a schema to track historical changes to patient insurance policies over time."

As a Software Engineer at Zelis Healthcare, you will design, develop, and maintain secure, scalable, and robust software applications that power the company's financial and payment platforms. This involves writing high-quality C# code, optimizing database performance, and building APIs that integrate seamlessly with external healthcare networks.

You will collaborate closely with product managers, QA engineers, and system architects to translate business requirements into technical designs. A significant portion of your role will involve ensuring that all applications meet stringent security and compliance standards, as well as participating in code reviews to maintain high engineering standards across the organization.

Additionally, you will be responsible for writing comprehensive unit and integration tests to guarantee system reliability. You will also participate in deploying applications to cloud environments and troubleshooting production issues to minimize system downtime.