Senior C#/.NET Engineer — Legacy Modernization on AWS

Brilliant Infotech Inc.; Hamilton (NJ); Hybrid; USD 130,000 - 180,000; Full time

Job summary

Brilliant Infotech Inc. is seeking an experienced C#/.NET Engineer to lead modernization of a legacy benefits system hosted on AWS. This contract, hybrid in Hamilton, NJ, role focuses on refactoring, service layer and API development, and performance optimization for nightly batch windows.

You will guide architectural decisions, mentor junior developers, and ensure functional equivalence with robust tests and CI/CD integration. Strong PostgreSQL/EF Core expertise is required.

Qualifications

• 12–15 years of professional C#/.NET experience with senior/lead responsibilities.
• Deep expertise in C#, .NET Framework/Core, async programming, and performance tuning.
• Expert EF Core: modeling, Fluent API, migrations, transactions.
• Strong PostgreSQL schema design, indexing, and query tuning.
• REST API design with ASP.NET Core Web API.
• Solid understanding of SOLID, layered architecture, and DI.
• Testing discipline with unit/integration/regression testing.
• Experience reading and safely refactoring large codebases; attention to accuracy in financial calculations.

Responsibilities

• Refactor COBOL-derived C# into idiomatic .NET with proper OO design.
• Build service layers, domain models, and APIs backing the Angular UI.
• Migrate legacy batch logic to maintainable .NET with accurate decimal math.
• Optimize batch performance to meet nightly SLAs.
• Lead data access with EF Core against PostgreSQL and migrations.
• Define coding standards and mentor developers.
• Ensure unit and regression tests; integrate with CI/CD and SonarQube.

Skills

C#/.NET

Async programming

EF Core

PostgreSQL

ASP.NET Core

Unit testing

Dependency Injection

Design patterns

Code refactoring

Git/CI/CD

AWS

Npgsql

SonarQube

CodeBuild/CodePipeline

Tools

AWS

Npgsql

SonarQube

AWS CodeBuild/CodePipeline

Job description

Brilliant Infotech Inc. is seeking an experienced C#/.NET Engineer to lead modernization of a legacy benefits system hosted on AWS. This contract, hybrid in Hamilton, NJ, role focuses on refactoring, service layer and API development, and performance optimization for nightly batch windows.

You will guide architectural decisions, mentor junior developers, and ensure functional equivalence with robust tests and CI/CD integration. Strong PostgreSQL/EF Core expertise is required.