.NET Mainframe Developer
Vienna , VA
Experience: 0
Category: Information Technology
Contractor Work Model: Remote
Brand: System One
Job ID: 350417
Date Posted: 05/06/2026
Shortcut: http://jobs.systemone.com/DZTWPC
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.
#M-
#LI-
Ref: #851-Rockville-S1
-
Java Mainframe Developer
Vienna , VA
Job Title: Java Developer Location: Remote Type: Contract Responsibilities Design, develop, and enhance complex software applications supporting mission-critical, time-sensitive initiatives focused on integrating distributed applications with the organ...
Date Posted: 05/06/2026 Recommended
-
Full Stack .NET Developer
Pensacola, FL
Full Stack .NET Developer .NET, JavaScript, React, Azure Cloud 10+ yrs of experience Hybrid 3 days a week on-site, Pensacola, FL Hourly Rate: $75-$80/hr. range W2 Multiyear Contract System One has a multi-year contract opening for a senior-level full-s...
Date Posted: 04/02/2026 Recommended
-
Application Architect
Bethesda, MD
Job Title: Application Architect Location: Bethesda, MD Type: Permanent salaried position Compensation: 170- 190K Contractor Work Model: Hybrid (2 to 3 days on site in Bethesda MD) The Senior Application Architect is responsible for developing and evol...
Date Posted: 04/17/2026 Recommended
-
Software Developer
Washington, District Of Columbia
Title: Software Developer Location: Washington, DC Clearance: Active Secret clearance/Top-Secret preferred Type: Direct Hire Contact: Crystaldinnocenti@systemone.com Successful Software Developer's demonstrate competency in integrating advanced technol...
Date Posted: 03/25/2026 Recommended
-
AEM Developer Architect
Centennial , Colorado
Job Title: AEM Developer Architect Location: Centennial, Colorado Type: Contract To Hire Contractor Work Model: Onsite Responsibilities Lead the design and development of enterprise-grade AEM solutions focusing on modularity, scalability, and maintaina...
Date Posted: 03/18/2026 Recommended
-
AEM Developer Architect
Centennial , Colorado
Job Title: AEM Developer Architect Location: Centennial, Colorado, United States Type: Contract To Hire Contractor Work Model: Onsite Hours: 40.0 Responsibilities Lead the design and development of enterprise-grade AEM solutions focusing on modularity,...
Date Posted: 04/03/2026 Recommended
-
Senior Software Engineer - Automation
Seaford, DE
Job Title: Senior Software Engineer, Automation Location: Seaford, DE or Northwest, AR Type: Direct Hire Job Summary: System One is seeking a Senior Software Engineer - Automation for a permanent opportunity near Seaford, DE or Northwest, AR. The Sr. S...
Date Posted: 05/06/2026 Recommended
-
Software Architect
Melbourne, FL
Job Title: Software Architect Location: Melbourne, FL Type: Direct Hire Responsibilities Help design, develop, and deliver high-quality software solutions that provide value across the organization. Provide architectural leadership throughout the full ...
Date Posted: 05/04/2026 Recommended
-
Mid level Java Developer
Washington, District Of Columbia
Full Stack Developer (UI focused) Washington, DC – hybrid (3 days a week onsite) Candidates must be able to work without sponsorship Must be able to obtain Public Trust clearance 6 month contract System One is seeking a mid-level Full Stack Developer t...
Date Posted: 05/05/2026 Recommended
-
Full-Stack Developer
NA, Virginia
Senior Full-Stack Developer (Python / Django / AWS) Location: Remote (EST Preferred) Type: Contract To Hire Contractor Work Model: Remote Responsibilities Work closely with clients, technical leads, and cross-functional teams to design and deliver scal...
Date Posted: 05/05/2026 Recommended
-
Full Stack Developer
Atlanta, Georgia
Full Stack Developer Mostly Remote but must be available for onsite work in Atlanta, GA as needed GC Holders and US Citizens per government contract Must be able to obtain Public Trust Clearance Compensation: up to $128K commensurate with experience As...
Date Posted: 04/30/2026 Recommended
-
Sr Software Engineer
Pittsburgh, PA
Tittle: Sr Software Engineer Location: Pittsburgh, PA (Locals Preferred) Work Mode : 5 Days Onsite Duration: Contract to Hire Years Of Exp Required: 8+ Years Function of the Group: Digital Transformer team supports online banking experience and functio...
Date Posted: 04/30/2026 Recommended
-
Mid Level DevOps Engineer
McLean, VA
Mid-Level DevOps Software Analyst Remote Candidates must be able to work without sponsorship W2 Employment only What You Will Do: As the DEVOPS Software Analyst you will be responsible for mission critical support of all department owned applications a...
Date Posted: 04/27/2026 Recommended
-
Senior IT Applications Developer
Pittsburgh, Pennsylvania
Job Title: Senior IT Applications Developer Location: Pittsburgh, PA Type: Direct Hire Contractor Work Model: Hybrid Senior IT Applications Developer to join an IT Applications team responsible for development, maintenance, customization, and configura...
Date Posted: 02/25/2026 Recommended
-
Senior Kubernetes Engineer / Platform Administrator
Washington, District Of Columbia
Senior Kubernetes Engineer / Platform Administrator Washington, DC (Bolling AFB) - onsite Active Top Secret with SCI eligibility We are seeking a highly experienced Senior Kubernetes Engineer / Platform Administrator to lead the design, deployment, and...
Date Posted: 03/20/2026 Recommended
-
Software Engineer Lead - JAVA
Pittsburgh, TX
Title - Software Engineer Lead Location - Pittsburgh, PA/Strongsville, OH Function of the Group: Liquidity Risk Management Initiatives/Projects: P-416801 Industry background: Banking-Regulatory Submissions (specifically FR-2052A), Liquidity Risk Manage...
Date Posted: 04/23/2026 Recommended
-
EDI Integration Engineer II
Seaford, DE
Job Title: EDI Integration Engineer II Location: Seaford, DE Type: Direct Hire Job Summary: System One is seeking an EDI Integration Engineer II for a permanent opportunity in Logistics and supply chain. This role is responsible for participating with ...
Date Posted: 05/01/2026 Recommended
-
Business Application Developer
Tampa, FL
Job Title: Business Application Developer Location: Tampa, FL Type: Direct Hire Security Clearance: Must Be Able to Obtain a DoD Secret Security Clearance Job Summary: System One is seeking a Business Application Developer for a full-time/permanent opp...
Date Posted: 04/27/2026 Recommended
-
DBA/Systems Engineer
Broken Arrow, Oklahoma
Job Title: DBA / Systems Engineer Location: Broken Arrow, Oklahoma Type: Contingency Compensation: $88,025.00 - $140,855.00 Contractor Work Model: Onsite MUST-HAVES: must be able to back-up database separate from server must be able to work extensively...
Date Posted: 04/03/2026 Recommended
-
.NET Developer
Kittery, Maine
Job Title: .NET Developer Location: Kittery, Maine Required : Currently active Secret Clearance If interested reach out directly to kimberly.spicer@systemone.com Required: .NET development experience, including custom database-driven web parts and time...
Date Posted: 04/13/2026 Recommended
-
Senior Azure Cloud Infrastructure Engineer
20892, Maryland
Job Title: Sr. Azure Cloud Infrastructure Engineer Location: Bethesda, MD Job Type: Contract to Hire Contractor Work Model: REMOTE but must be located in the DC/VA/MD or surrounding areas Security Clearance: candidates must be eligible to obtain a Publ...
Date Posted: 05/05/2026 Recommended
-
Software Development Engineer (SDET)
Merrifield, VA
Job Title: Senior Software Development Engineer (SDET) Location: Hybrid Work Model Reporting to Vienna, VA, Pensacola, FL, San Diego, CA Pay Rate: Open to Both C2C and W2 options Position Type: Multiyear Contract Responsibilities Work with engineers to...
Date Posted: 03/20/2026 Recommended
-
Software Engineer Lead
Pittsburgh, PA
Software Engineer Lead Pittsburgh, PA Contract to Hire | Onsite – 5 Days/Week Interview: 1st round is virtual with a panel. 2nd round is in-person (Coding Round) Job Summary The Software Engineer Lead serves as the primary technical authority for the t...
Date Posted: 03/24/2026 Recommended
-
Senior Back End Software Developer
Colorado Springs, Colorado
Senior Back End Software Developer Location: Colorado Springs, Colorado Work Model: Onsite Clearance: Eligible – will be processed for Top Secret eventually If interested reach out directly to kimberly.spicer@systemone.com or text 301-252-8762 Responsi...
Date Posted: 05/01/2026 Recommended
-
Bus Systems Analyst Lead
Farmers Branch, TX
Title: Business Systems Analyst Lead Position Location: Dallas, TX/Pittsburgh, PA/ Cleveland, OH - 5 Days Onsite Function of the Group: Mitigates Risk Initiatives/Projects: The resource will assist with ongoing change requests, automation enhancements,...
Date Posted: 03/09/2026 Recommended
-
Sr Healthcare Software Tester / QA Analyst
Washington, District of Columbia
Job Title: Sr Healthcare Software Tester / QA Analyst Location: Washington, District of Columbia Type: Contract To Hire Compensation: $60/hour Contractor Work Model: Hybrid – onsite 1-2 days per week Hours: 40.0 Overview -Must have automation with some...
Date Posted: 05/04/2026 Recommended
-
Forgerock Developer
Salt Lake City, Utah
Job Title: Forgerock Developer Location: Salt Lake City, Utah Type: Contract To Hire Compensation: $0.00 Contractor Work Model: Onsite – onsite Hours: 40.0 Security Clearance: Not specified Overview Leave placeholder text here for recruiter to input Re...
Date Posted: 04/10/2026 Recommended
-
Business Analyst - SAP
Tulsa , Oklahoma
Job Title: Business Analyst - SAP Location: Tulsa, Oklahoma, United States Type: Direct Hire Compensation: $90,000.00 - $135,000.00 Contractor Work Model: Hybrid Job Description Responsibilities Own business processes from the IT perspective while bein...
Date Posted: 05/05/2026 Recommended
-
Senior DevOps Engineer
McLean, VA
Sr. DevOps Engineer Candidates must be able to work in the U.S. without sponsorship 100% Remote W2 ONLY As the DEVOPS Software Analyst you will be responsible for mission critical support of all department owned applications and their infrastructure. Y...
Date Posted: 04/28/2026 Recommended
-
Software Engineer Lead
Strongsville, OH
Position Title: Software Engineer Lead Location: Pittsburgh, PA/Cleveland, OH Initiatives/Projects: optimizing the existing application to reduce spend year over year. Industry background: Banking/financial is preferred Team Dynamic: Working in a crew ...
Date Posted: 04/15/2026 Recommended