Senior .NET Software Engineer

Senior .NET Software Engineer

Location: Remote (USA) | Contract

Schedule: Monday-Friday, 8:00 AM - 5:00 PM. Equipment will be provided where approved; otherwise candidates use their own PC/Mac with a virtual desktop.

Overview

Our client is seeking a Senior .NET Software Engineer to lead the maintenance, modernization, and ongoing evolution of a mission-critical, dealer-facing payment platform that enables key transactions directly supporting revenue and day-to-day operations. As a technical leader, you'll design, develop, and support backend services and applications, balancing a mature production environment with ongoing modernization, contributing to architecture and technical direction, and ensuring reliability, scalability, security, and performance. The role includes ownership of applications in production, in close partnership with product, operations, and business stakeholders.

Responsibilities

• Design, develop, test, and maintain backend services and APIs supporting enterprise payment solutions.
• Participate in Agile ceremonies, including iteration planning, standups, and retrospectives, and help drive continuous improvement.
• Collaborate with product, engineering, and business stakeholders to deliver customer-focused solutions.
• Contribute to the architecture, development, and operation of scalable microservices and distributed systems.
• Apply engineering best practices, including clean code, test-driven development, code reviews, and automated testing.
• Build and maintain CI/CD pipelines and deployment processes that support reliable software delivery.
• Monitor, troubleshoot, and support applications in production.
• Contribute to the codebase while ensuring adherence to coding standards, security requirements, and best practices.

Required Qualifications

• 4+ years of software development experience using C# and the .NET framework, designing, developing, maintaining, and enhancing enterprise applications
• Experience designing and building REST APIs, including documentation (Swagger/OpenAPI), versioning, testing, and service integration patterns
• Strong understanding of software development concepts, object-oriented design principles, and modern engineering practices
• Solid knowledge of relational database design, indexing strategies, query optimization, and SQL development
• Experience with test-driven development and testing frameworks such as xUnit, NUnit, or MSTest
• Experience with CI/CD and DevOps tools such as GitHub, Azure DevOps, Jenkins, or SonarQube
• Experience developing and supporting production services and implementing observability with Datadog or equivalent tools
• Experience with containerization technologies such as Kubernetes and Docker
• Familiarity with modernizing applications toward current .NET platforms, including .NET 8
• Excellent problem-solving, troubleshooting, communication, and interpersonal skills
• Experience working in an Agile/Scrum or Extreme Programming (XP) environment

Preferred Qualifications

• Bachelor's degree, or an equivalent combination of education and experience
• Experience with .NET Core and modern .NET application development patterns
• Experience with Java and frameworks such as Spring Boot, Spring Data, or Spring Security
• Experience building and operating high-traffic, distributed systems that support large transaction volumes
• Experience with quality and security scanning tools such as SonarQube, Fortify, or Contrast
• Experience with Kafka or similar event-streaming platforms
• Practical cloud experience with AWS, PCF, Azure, or other platforms, plus application performance monitoring tools

Pay rate: $55/hr (W2). This is a 3-month contract position, 100% remote in the USA.