Senior .Net Full Stack Software Engineer

Zelis • St. Louis, MO

1d • Hybrid

About The Position

At Zelis, we Get Stuff Done. So, let’s get to it! A Little About Us Zelis is modernizing the healthcare financial experience across payers, providers, and healthcare consumers. We serve more than 750 payers, including the top five national health plans, regional health plans, TPAs and millions of healthcare providers and consumers across our platform of solutions. Zelis sees across the system to identify, optimize, and solve problems holistically with technology built by healthcare experts – driving real, measurable results for clients. At Zelis, AI is woven into the fabric of how we work. Every associate is expected - and empowered - to partner with AI to challenge the status quo, accelerate innovation, and amplify their impact. This is a place for builders with a growth mindset who act with agility, embrace change, and use modern technology to shape smarter solutions, exceptional experiences, and the future of our industry for our clients, customers, and our culture. A Little About You You bring a unique blend of personality and professional expertise to your work, inspiring others with your passion and dedication. Your career is a testament to your diverse experiences, community involvement, and the valuable lessons you've learned along the way. You are more than just your resume; you are a reflection of your achievements, the knowledge you've gained, and the personal interests that shape who you are. Position Overview We are seeking a Senior .NET Full Stack Software Engineer to design, build, and operate core backend and full-stack systems for our healthcare payments and AI-driven solutions. This role is ideal for an engineer with deep backend expertise who enjoys working across the stack and is passionate about building scalable, secure, and reliable solutions in the cloud.

Requirements

• Bachelor’s or Master’s degree in Computer Science or a related technical field, or equivalent practical experience.
• 8+ years of professional software engineering experience, primarily focused on backend systems.
• Strong expertise in C#, .NET Core / .NET 8+, ASP.NET Core Web APIs & Microservices.
• Experience building and operating web-based services and APIs, especially for payment and digital identity solutions.
• Experience with SQL Server (complex queries, performance tuning) and cloud platforms (preferably AWS).
• Familiarity with Infrastructure as Code, CI/CD pipelines, and automated delivery processes.
• Proven ability to deliver reliable, maintainable software in production environments.
• Strong written and verbal communication skills.
• Collaborative mindset, positive attitude, and desire to continuously learn and improve.

Nice To Haves

• Experience with Angular, React, or similar frontend frameworks.
• Experience with containerization (Docker, Kubernetes), service-oriented architectures, or distributed systems.
• Exposure to observability tooling (logging, metrics, tracing).
• Experience using AI-assisted tools or developing AI-driven applications (e.g., chatbots).
• Experience with financial transactions, reconciliation, and reporting systems.
• AWS certifications

Responsibilities

• Design, develop, test, deploy, and maintain high-quality backend services and supporting systems using .NET Core / .NET 8+.
• Lead the end-to-end development of payment processing, digital identity, and AI-powered solutions.
• Own services in production, including deployment, monitoring, performance, and operational health.
• Collaborate with product managers, designers, and cross-functional teams to translate requirements into technical solutions.
• Drive architectural decisions with a focus on scalability, reliability, security, and maintainability.
• Ensure compliance with PCI-DSS, HIPAA, and internal security standards.
• Improve development and delivery workflows, including CI/CD pipelines and infrastructure automation.
• Mentor engineers and provide technical leadership through design reviews, code reviews, and architectural guidance.
• Troubleshoot and resolve production issues and system bottlenecks.

Benefits

• 401k plan with employer match
• flexible paid time off
• holidays
• parental leaves
• life and disability insurance
• health benefits including medical, dental, vision, and prescription drug coverage

What This Job Offers

• Job Type: Full-time
• Career Level: Senior