> Markdown version of [/jobs/ext/4389514-senior-software-engineer](https://www.wearedevelopers.com/jobs/ext/4389514-senior-software-engineer). Every page supports `.md` or `Accept: text/markdown`. Links point to the HTML versions so they work for humans too. Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md).

---

# Senior Software Engineer

- **Company:** Fiserv, Inc.
- **Location:** Sunnyvale, CA, United States
- **Experience:** Expert
- **Salary:** $160,000.0 - $240,000.0
- **Contract:** Permanent contract
- **Skills:** ASP.NET, Java (Programming Language), .NET Framework, Application Programming Interfaces (APIs), Amazon Web Services, User Authentication, Microsoft Azure, C Sharp (Programming Language), Cloud Computing, Databases, Database Design, Software Debugging, JSON, Microsoft Visual Studio, MySQL, OAuth, Clover, SQL Databases, Systems Integration, TypeScript, ReactJS, Backend, Git, Integration Frameworks, Codebase, Restful APIs, Webhooks, Docker
- **Published:** October 6, 2026
- **Apply:** https://www.techcareers.com/job.asp?id=3426309296&tx=DT11606UHI&pt=1&aff=0B19D771-A501-4A5E-8338-2A822B784D54&utm_source=Job%20Feed&utm_medium=textkernel&utm_campaign=DE&utm_term=0B19D771-A501-4A5E-8338-2A822B784D54

## About the Role

* C# & .NET 8 / ASP.NET Core: Strong backend development skills for building high-performance RESTful Web APIs.
 * Legacy .NET Framework Familiarity: Comfort working with or supporting code written in legacy .NET Framework codebases.
 * Raw MySQL & Hand-Crafted SQL: Excellent proficiency in writing, debugging, and optimizing complex raw SQL queries without reliance on ORMs.
 * Multi-Tenant Architecture: Experience with multi-tenant database designs, tenant isolation strategies, and efficient connection handling.
 * REST APIs & Webhooks: Experience building and consuming RESTful endpoints, processing JSON payloads, and managing Webhook events for third-party integrations.
 * OAuth 2.0 & Authentication: Understanding of token management and securing external API communication.
 * IDE & Tooling: Proficiency in Visual Studio for backend development and debugging.
 * Git Version Control: Hands-on experience using Git within environments like Azure DevOps.
 * Docker & Basic Cloud Context: Experience using Docker for local development setup and familiarity working within cloud-hosted environments (AWS / GCP).

What would be great to have:

 * Java Background (Bonus): Exposure to Java backend technologies is a plus, as parts of the ecosystem may leverage Java in future iterations.
 * Experience with React and Typescript

## Description

As a .NET Software Engineer at Clover, you will design, build, and maintain high-performance backend systems and RESTful APIs using C# and .NET 8. Working with complex multi-tenant database architectures and cloud-hosted environments, you will drive seamless integrations with third-party platforms while ensuring robust security, performance, and reliability across our applications.

What you will do:

 * Build high-performance RESTful Web APIs using C# and ASP.NET Core.
 * Support and maintain existing code written in legacy .NET Framework codebases.
 * Write, debug, and optimize complex raw SQL queries in MySQL and manage multi-tenant database architectures.
 * Develop and consume RESTful endpoints, process JSON payloads, and manage Webhook events and OAuth 2.0 authentication for third-party integrations.
 * Utilize Visual Studio, Git (Azure DevOps), Docker, and cloud-hosted environments (AWS / GCP) for development and deployment.