Software Engineer (.NET/React + SDK Architecture)
Software Engineer (.NET/React + SDK Architecture)
Madison, Wisconsin
|Full Time Temp to Hire
|NA
Madison, Wisconsin
Full Time Temp to Hire
NA
September 29, 2025
|Job ID: SMA92925MAD_1759154989
September 29, 2025
Job ID: SMA92925MAD_1759154989
Job Summary
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Location: Hbyrid WFH - Greater Madison Area
Duration: Open; initial 6-12 months with potential extension
Number of positions- 2-3
Equipment -candidates must use their own equipment.
Currently seeking a Software Engineer with strong .NET Core (C#) and React.js development experience, ideally combined with hands-on knowledge of Fiserv SDKs (Architect SDK, FirstAPI). This role will support financial product integrations, focusing on mobile and web SDK implementation, secure API connections, and ACH payment workflows.
Candidates with direct Fiserv SDK experience are highly preferred. However, strong .NET and React engineers who can learn and adapt quickly to the SDK will also be considered.
Key Responsibilities
- Design, develop, and maintain software using .NET Core (C#) and React.js.
- Integrate Fiserv Architect SDK for mobile and web applications.
- Implement server-to-server and client integrations with Fiserv FirstAPI Gateway.
- Work with RESTful APIs secured via HMAC authentication, OAuth2 session tokens, and payload encryption.
- Support ACH payment workflows, including enrollment, tokenization, updates, and account closure.
- Configure and customize SDK-driven UI workflows (multi-step screens, multilingual, error handling).
- Ensure secure management of API keys, secrets, and tokens, following compliance and security best practices.
- Collaborate with cross-functional stakeholders (architecture, engineering, product) to align designs with business needs.
- Troubleshoot and resolve integration issues across SDK, APIs, and backend systems.
Required Qualifications
- 5+ years of software engineering experience.
- Strong skills in .NET Core (C#) and React.js development.
- Familiarity with SDK integration (mobile/web), especially in financial services or payments.
- Knowledge of API integration patterns (REST, OAuth2, HMAC, encryption).
- Experience working in enterprise architecture environments with scalability and compliance requirements.
- Strong analytical, debugging, and problem-solving skills.
Preferred Qualifications
- Hands-on experience with Fiserv Architect SDK and Fiserv FirstAPI gateway.
- Understanding of ACH payments, tokenization, and secure data flows.
- Experience with mobile SDK integration (iOS, Android) in addition to web.
- Located in Madison, WI (preferred) or MN/IL.
SMA92925MAD_1759154989
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About Beacon Hill
Beacon Hill is an Equal Opportunity Employer that values the strength diversity brings to the workplace. Individuals with Disabilities and Protected Veterans are encouraged to apply.
Founded by industry leaders to set a new standard in search, career placement and flexible staffing, we deliver coordinated staffing solutions with unparalleled service, a commitment to project completion and success and a passion for innovation, creativity and continuous improvement.
Our niche brands offer a complete suite of staffing services to emerging growth companies and the Fortune 500 across market sectors, career specialties/disciplines and industries. Over time, office locations, specialty practice areas and service offerings will be added to address ever changing constituent needs.
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