Senior Mainframe Developer Jobs in Washington (NOW HIRING)

Job Title: .NET Developer Location: Remote Type: Contract Contractor Work Model: Remote

Responsibilities

• Design, develop, and enhance complex software applications supporting mission-critical, time-sensitive initiatives focused on integrating distributed applications with the organization's Core Banking platform.
• Serve as a senior technical contributor responsible for translating business and platform requirements into secure, scalable, and reliable solutions across the full software development lifecycle.
• Operate with minimal supervision while exercising strong technical judgment.
• Collaborate with Core Banking, testing, middleware, and platform teams to manage dependencies, mitigate risk, and meet aggressive delivery timelines.
• Design, develop, and optimize high-quality software applications using various, advanced programming languages and frameworks that meet business requirements.
• Collaborate with stakeholders and team members to gather and analyze requirements, translate requirements into technical specifications, propose innovative solutions, and ensure timely task completion.
• Write clean, scalable, and maintainable code that adheres to industry best practices and organizational coding standards.
• Implement data structures and algorithms efficiently, optimizing code for performance, scalability, and user experience.
• Identify, troubleshoot, and resolve errors in application function.
• Conduct team code reviews, provide constructive feedback, and learn from colleagues' expertise to maintain a high-quality codebase.
• Lead small efforts, while building strong working relationships with stakeholders, team members, and subject matter experts.
• Contribute to generating and adhering to application and software development policies, standards, and procedures.
• Continuously learn from individual and team experiences, fostering growth and improvement through collaboration and continuous feedback.

• Bachelor’s degree in Computer Science, Information Systems, or related field, or the equivalent combination of education, training, or experience.
• 5-7 years of experience in application or software development.
• Advanced proficiency in software development principles, methodologies (including Agile), pipelines, and version control systems (Git and GitHub).
• Expertise in programming languages / standards / build tools including Java, XML, Open API, Maven, and ANT, with strong knowledge of modern frameworks and libraries.
• Deep understanding of web technologies and technical applications, capable of designing and implementing scalable solutions.
• Strong problem-solving, analytical, and troubleshooting skills, with the ability to address complex technical issues efficiently.
• Advanced written and verbal communication skills for articulating technical concepts to both technical and non-technical stakeholders.
• Experience using incident tracking, project management, and change control software tooling.
• Expertise in data structures, algorithms, and applying them in the design and build of applications for optimal performance and scalability.
• Demonstrated experience with application development (web, desktop, or mobile) using C#, ASP.NET, and the Microsoft technology stack.
• Experience writing and maintaining unit and integration tests; troubleshooting and resolving software defects.
• Experience integrating data storage solutions (like SQL Server) and third-party APIs into application architectures.
• Familiarity with ASP.NET Core, MVC, and the broader .NET ecosystem (.NET 4.x or .NET 6/8+).
• Experience developing web services, microservices, RESTful APIs, and designing implementing common patterns and REST principles.
• Knowledge of Continuous Integration & Delivery (CI/CD) pipelines and tools.

Available for a 12-month contract, providing an excellent opportunity to work on mission-critical projects within a dynamic team environment.

System One, and its subsidiaries including Joulé and Mountain Ltd., are leaders in delivering outsourced services and workforce solutions across North America. We help clients get work done more efficiently and economically, without compromising quality. System One not only serves as a valued partner for our clients, but we offer eligible employees health and welfare benefits coverage options including medical, dental, vision, spending accounts, life insurance, voluntary plans, as well as participation in a 401(k) plan.

System One is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex (including pregnancy, childbirth, or related medical conditions), sexual orientation, gender identity, age, national origin, disability, family care or medical leave status, genetic information, veteran status, marital status, or any other characteristic protected by applicable federal, state, or local law.

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Ref: #851-Rockville-S1