Senior .NET Engineer - COBOL Modernization Lead

SmartIMS Inc.; Village of Hamilton (NY); On-site; USD 120,000 - 190,000; Full time

Job summary

SmartIMS Inc. is seeking a Sr. .NET Developer to modernize a COBOL-derived codebase into a maintainable .NET solution. You will design & implement ASP.NET Core Web APIs that power the Angular front end, and refactor legacy batch logic with exact decimal/financial calculations.

You will lead EF Core data access against PostgreSQL, optimize performance, and ensure high-quality delivery with unit tests and CI/CD integration. Mentoring and architectural guidance are key parts of the role.

Qualifications

• 15 years of professional C#/.NET software engineering with senior/lead responsibilities.
• Deep expertise in C#/.NET including async programming and modern language features.
• Expert-level EF Core: modeling, migrations, queries, concurrency.

Responsibilities

• Refactor COBOL-derived C# into idiomatic, maintainable .NET.
• Design and implement ASP.NET Core Web API back-end for Angular UI.
• Refactor legacy batch logic to ensure correctness and performance.
• Collaborate on CI/CD, quality gates, and security standards.
• Mentor mid/junior developers and perform code reviews.

Skills

Senior-level C#/.NET

Async programming

Unit/integration testing

Code reviews/mentoring

Design patterns/SOLID

Read/refactor large codebases

Performance optimization

CI/CD practices

AWS usage

PostgreSQL database design

Entity Framework Core

Tools

EF Core

ASP.NET Core Web API

PostgreSQL

AWS (ECS/EKS, RDS, S3)

Npgsql

Job description

SmartIMS Inc. is seeking a Sr. .NET Developer to modernize a COBOL-derived codebase into a maintainable .NET solution. You will design & implement ASP.NET Core Web APIs that power the Angular front end, and refactor legacy batch logic with exact decimal/financial calculations.

You will lead EF Core data access against PostgreSQL, optimize performance, and ensure high-quality delivery with unit tests and CI/CD integration. Mentoring and architectural guidance are key parts of the role.