Sr Software Engineer (React, JavaScript, .net)

Join the Client Services technology team as a Full-Stack Web Developer to build and enhance the high-value, data-driven applications that power our global support operations. In this role, you will work across a modern tech stack-utilizing React and TypeScript on the front end alongside C# and ASP.NET Core on the back end-to turn complex business data workflows into secure, scalable, and intuitive user experiences. By partnering with cross-functional business and technical teams, your engineering output will directly improve operational readiness, speed-to-market, and the overall efficiency of our client-facing services ecosystem., * Design, develop, and maintain responsive web applications using React and ASP.NET Core to support modern Single Page Application (SPA) experiences.

• Build, evolve, and support robust RESTful APIs and backend microservices in C# with a strong emphasis on maintainability, scalability, and clean architecture.
• Translate complex business needs into well-structured technical solutions, including UI workflows, API contracts, and performant data models.
• Develop, optimize, and maintain SQL Server database schemas, T-SQL queries, stored procedures, and advanced indexing strategies to support high-volume data use cases.
• Implement enterprise-grade security practices, including secure coding patterns, robust authentication/authorization protocols, and least-privilege access controls.
• Create reusable, tested front-end components and backend services using modular design patterns that facilitate long-term codebase health.
• Collaborate closely with product owners, technical analysts, and cross-functional support teams to reliably deliver features from concept and build to release and support.
• Participate actively in code reviews, system troubleshooting, performance tuning, and production monitoring to ensure top-tier software quality.
• Contribute to essential technical documentation, including design notes, operational runbooks, and supportability guides to enhance team velocity.
• Responsibilities listed are not intended to be all-inclusive and may be modified as necessary., * This role is on-site Monday through Friday. Fiserv considers in-person collaboration to be an essential part of this role as in-person office experiences help you with your overall onboarding experience and leads to stronger productivity.
• This role requires use of a computer and audio equipment.

• Bachelor's degree in Computer Science, Management Information Systems (MIS), or equivalent practical/professional work experience.
• 5+ years of professional hands-on experience designing, building, delivering, and supporting full-stack web applications.
• Strong backend proficiency in C# and modern .NET development (ASP.NET Core).
• Strong frontend proficiency in React utilizing modern patterns, including functional components, custom hooks, and component design.
• Production experience using TypeScript and modern JavaScript (ES6+) alongside HTML5 and CSS3 with an awareness of responsive layouts and accessibility.
• Solid database expertise with SQL Server and T-SQL, including data modeling, advanced querying, and schema optimization.
• Proven experience building, securing, and consuming REST APIs for client-device and web-client interactions.
• Familiarity with modern software development practices, including Git-based version control (advanced branching and merging), CI/CD concepts, automated unit/integration testing, and log-based production troubleshooting.
• Excellent written and verbal communication skills with the ability to work cross-functionally and translate business requirements into software solutions.

Experience that would be great to have:

• Experience utilizing Entity Framework Core or an equivalent Object-Relational Mapping (ORM) framework.
• Practical experience implementing authentication and authorization standards (e.g., OAuth2, JWT, or Microsoft Entra ID).
• Familiarity with containerization (Docker) and deploying workloads across cloud ecosystems (Azure/AWS) or hybrid/on-prem environments.
• Knowledge of asynchronous messaging patterns, queuing architectures, and background processing jobs.
• Exposure to enterprise reporting, data analysis, or embedded analytics tools such as SSRS or Power BI.
• Previous engineering experience within the payments, fintech, or financial services industries.
• Comfort working with modern engineering tooling, including Visual Studio/VS Code, SSMS, Azure DevOps, GitHub Actions, or IIS., * You must currently possess valid and unrestricted U.S. work authorization to be considered for this role. Individuals with temporary visas including, but not limited to, F-1 (OPT, CPT, STEM), H-1B, H-2, or TN, or any candidate requiring sponsorship, now or in the future, will not be considered for this role.

• Fuel Your Life program to support your physical, financial, social, and emotional well-being
• Paid holidays and generous time away policies
• No-cost mental health support through Employee Assistance Programs
• Living Proof program to recognize your peers' extra effort with points redeemable for rewards
• Eight Employee Resource Groups to foster a collaborative culture and expand your network
• ·Unparalleled professional growth with training, development, and internal mobility opportunities
• Medical, dental, vision, life, and disability insurance options available from day one
• Retirement planning and discounted shares with the Employee Stock Purchase Plan
• Tuition assistance and reimbursement program
• Paid parental, caregiver, and military leave

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Salary Range:

$90,000.00-$127,000.00

These pay ranges apply to employees in Maryland. Pay ranges for employees in other states may differ. Certain Positions are Commissions eligible.

It is unlawful to discriminate against a prospective employee due to the individual's status as a veteran.

We're Fiserv, a global leader in Fintech and payments, and we move money and information in a way that moves the world. We connect financial institutions, corporations, merchants, and consumers to one another millions of times a day - quickly, reliably, and securely. Any time you swipe your credit card, pay through a mobile app, or withdraw money from the bank, we're involved. If you want to make an impact on a global scale, come make a difference at Fiserv.