Lead C#​/.NET Engineer

We are modernizing a large, mission-critical Honeywell Bull mainframe benefits system (FAMIS) — converting ~1.5M lines of COBOL and ~160K lines of JCL to C#/.NET, migrating an IDS-II hierarchical database to PostgreSQL, and deploying on AWS. Converted code is delivered by an automated modernization vendor in an "as-is" state. This Lead/Principal role owns the refactoring of that converted code into clean, maintainable, high-performance, production-grade C#/.NET,

defines the data-access architecture using Entity Framework Core against PostgreSQL, sets engineering standards for the team, and safeguards functional equivalence to the legacy system. This is a benefits system serving NJ families — correctness, performance within the nightly batch window, and maintainability are paramount.

• C# Programming Experience Required 10 Years
• .NET Core / .NET 6/7/8/10 Experience Required 10 Years
• .NET REST/WEB API Development Experience Required 5 Years
• Entity Framework Core and LINQ and async/await patterns Experince Required 10 Years
• Solid software design: SOLID, design patterns, domain modeling, layered/clean architecture, dependency injection Required 5 Years
• Angular 17+, Typescript and Node.js experience Required 5 Years
• Strong relational database skills;
  PostgreSQL strongly preferred (Oracle/SQL Server acceptable) — schema design, indexing, query tuning, stored proc Required 5 Years
• unit/integration/regression testing frameworks; TDD/mocking Required 5 Years
• Git and static code analysis (Sonar Qube) Required 5 Years
• Docker containerization and CI/CD pipeline experience (AWS CODE PIPELINE OR Git Hub Actions) Required 3 Years
• AWS cloud native applications (S3, SNS, SQS, ECS, RDS, EC2, Lambda) Required 3 Years

• C# / .NET Engineering
• Refactor machine-converted, COBOL-derived C# into idiomatic, maintainable .NET — meaningful naming, proper OO/domain design, separation of concerns, dependency injection
• Work in .NET (Core) / .NET (latest version); apply modern C# language features (LINQ, async/await, records, pattern matching, nullable reference types, generics)
• Design and implement service layers, domain models, and APIs (ASP.NET Core Web API) that back the Angular UI
• Refactor legacy batch/procedural logic (converted from COBOL/JCL) into maintainable, testable .NET; handle exact decimal/financial arithmetic (decimal, rounding rules) to preserve benefit-calculation correctness
• Optimize performance to meet the nightly batch window (profiling, memory management, async I/O, parallelism where safe)
• Entity Framework / Data Layer
• Own the data-access architecture using Entity Framework Core against PostgreSQL (Npgsql provider)
• Refactor the auto-generated/converted data-access layer into a clean, performant EF Core model
• Design entity models, DbContext configuration, Fluent API mappings, relationships, keys, and indexes reflecting the IDS-II → PostgreSQL schema (168 tables, 4,024+ fields)
• Optimize EF Core queries (eager/lazy/explicit loading, projection, As No Tracking , compiled queries, batching) to avoid N+1 and meet performance SLAs on high-volume batch operations
• Manage EF Core migrations, concurrency handling, transactions, and connection resiliency
• Map legacy data types and semantics correctly (packed decimals, fixed-width, EBCDIC-origin data, condition codes) to PostgreSQL/EF types without behavioral drift
• Contribute to the COBOL-field → PostgreSQL-column → business-term data dictionary
• Technical Leadership
• Define and enforce C#/.NET coding standards, architecture patterns, and refactoring guidelines for the engineering team
• Serve as senior technical authority on the converted codebase;…