.NET Developer – Legacy System Decommissioning (On-Site, NYC)

 

<>.NET Developer – Legacy System Decommissioning (On-Site, NYC)

Location: New York, NY 10038 (66 John Street, 11th Fl.) —
On-site Mon–Fri, no remote
Job Type: Contract
Duration: 7 months+
Hours: 35 hrs/week or 7 hours per day only
Role: .NET Developer / Programmer 2

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About the Role

We are seeking a skilled .NET Developer to support the decommissioning of a legacy adjudication system. This is a dual-focus role: roughly 60% application development and 40% system decommissioning.

You will help retire a legacy Java-based system — including its services, databases, and infrastructure — while also designing, building, and maintaining modern .NET applications. This is a hands-on technical role requiring strong backend, database, and integration skills, plus the discipline to execute controlled system shutdowns with full documentation.

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What You'll Do

Application Development (60%)

• Design, develop, and maintain applications using ASP.NET, Web Forms, Entity Framework, and Web APIs

• Build new web services and enhance existing applications

• Support system integrations, testing, and deployment

• Troubleshoot, optimize performance, and provide ongoing technical support

• Work with modern tech as needed: .NET Core / .NET 6+, RESTful APIs, microservices, AWS/Azure, React/Angular/Vue, Docker/Kubernetes, SQL Server/NoSQL/MongoDB

System Decommissioning (40%)

• Perform system inventory, dependency mapping, and impact analysis across integrated systems

• Decommission application code, APIs, and batch processes in a controlled manner

• Extract, archive, and/or migrate data per retention policies, with validation for data integrity

• Retire application services, middleware, infrastructure, and third-party components

• Develop decommissioning plans, runbooks, and validation documentation

• Execute testing and coordinated system shutdown with stakeholders

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Mandatory Qualifications

Candidates without ALL of the following will not be considered:

Backend

• 6+ years as a Programmer in .Net Development.

• C# — strong backend development with clean, maintainable, performant code

• ASP.NET MVC — building scalable web applications

• .NET Core — hands-on, cross-platform, high-performance development

Data & ORM

• Entity Framework (EF Core or EF 6) — Code First / Database First

• Proficient in LINQ, EF migrations, query optimization, and complex data relationships

• SQL Server 2019 — database design, optimized queries, stored procedures, performance tuning

Web Services

• RESTful APIs — design and consume using ASP.NET Core Web API

• SOAP web services, WSDL, and XML-based services

Frontend

• HTML5 / CSS3 — responsive UI development

• JavaScript (ES6+)

• Angular 8 — SPAs (components, directives, services, routing)

Reporting

• SSRS — interactive, parameterized reports in web apps

• Crystal Reports — design, generate, and embed reports

Architecture & Quality

• MVC architecture and design patterns (Repository, Factory, Singleton)

• Unit testing / TDD — XUnit, MSTest, or NUnit

DevOps & Security

• Git version control

• CI/CD — Azure DevOps, Jenkins, or GitLab CI

• Authentication/Authorization — OAuth, JWT, RBAC

Soft Skills

• Excellent verbal/written communication with diverse stakeholders

• Strong analytical and problem-solving abilities; a true team player

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Preferred (Nice-to-Have)

• Microservices architecture

• Performance optimization (frontend, backend, and database queries)

• Docker / Kubernetes containerization

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Important Requirements

• On-site presence is mandatory Monday–Friday at 66 John Street, NYC — local candidates strongly preferred

• Must pass fingerprint and criminal background checks (NY State DCJS + FBI) prior to award

• Must sign a non-disclosure agreement

• Must be legally authorized to work in the United States

• References required: at least three former or current clients for similar work

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How to Apply

If you meet the mandatory qualifications and are available for an on-site NYC contract starting October 1, 2026, please apply with your updated resume and contact information. Qualified candidates will be contacted for in-person and/or telephone interviews.