Job Listing Information

Lead/Principal C#/.NET Engineer
  • 09-Oct-2026 to 23-Oct-2026 (UTC)
  • Hamilton, NJ, USA
  • Full Time
  • Long Term Contract Length
  • 40 Weekly Hours

Position Summary

- 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.

 

Key Responsibilities

- 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, AsNoTracking, 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; make cross-cutting design decisions

- Mentor mid/junior C# developers; perform code reviews; drive engineering quality

- Partner with the Technical Manager/Architect on target architecture and the refactoring strategy

 

Quality, Testing & Delivery

- Ensure functional equivalence: build unit and regression tests (xUnit/NUnit, Moq) to validate refactored code against the legacy baseline; fix FET-surfaced defects

- Integrate with CI/CD (AWS CodeBuild/CodePipeline), enforce quality/security gates (SonarQube, static analysis, secure coding/OWASP)

- Collaborate with FAMIS SMEs to preserve business logic (eligibility, benefit calculation, payments, EBT)

- Deliver incrementally within Scrum; document design and decisions

 

Required Qualifications

- 12-15 years of professional C#/.NET software engineering, including senior/lead responsibilities

- Deep expertise in C# and the .NET platform (.NET Framework and .NET Core / .NET 6/8+), including async programming, memory/performance optimization, and modern language features

- Expert-level Entity Framework / EF Core: entity modeling, Fluent API, migrations, query optimization, transactions, concurrency, provider-specific behavior

- Strong relational database skills; PostgreSQL strongly preferred (Oracle/SQL Server acceptable) — schema design, indexing, query tuning, stored procedures

- ASP.NET Core Web API design (REST) for front-end integration

- Solid software design: SOLID, design patterns, domain modeling, layered/clean architecture, dependency injection

- Testing discipline: unit/integration/regression testing frameworks; TDD/mocking

- Git, CI/CD, and static code analysis (SonarQube)

- Proven ability to read, reason about, and safely refactor large, unfamiliar codebases

- Exceptional attention to correctness — financial/benefit calculation accuracy

 

Preferred / Nice to Have

- Legacy modernization experience — COBOL-to-C#/Java conversion, mainframe migration, or automated-transformation tooling

- Understanding of mainframe concepts (COBOL, JCL, batch processing, hierarchical/CODASYL databases like IDS-II/IMS) — to reason about source behavior

- High-volume batch processing performance tuning

- AWS experience (ECS/EKS, Lambda, RDS for PostgreSQL, S3, CloudWatch, IaC/CloudFormation)

- Experience integrating with enterprise job schedulers (Stonebranch, Control-M, CA7)

- Government / benefits / healthcare or other regulated, high-correctness domains

- Npgsql specifics, EF Core performance internals, or ORM migration experience

 

Success in the First 90 Days

- Establish the C#/.NET and EF Core standards, patterns, and reference implementation the team will follow

- Refactor a representative set of converted programs (including a benefit-calculation and a batch program) to clean, tested, performant C# validated against the legacy baseline

- Define the EF Core data-access approach against PostgreSQL, including query-performance guardrails for batch workloads

- Mentor the team and set the code-review/quality bar

 

Fill the skill matrix below:

Skill

Required/Desired

Amount

Candidate's No. of years of experience

C# Programming Experience

Required

10

 

.NET Core / .NET 6/7/8/10 Experience

Required

10

 

.NET REST/WEB API Development Experience

Required

5

 

Entity Framework Core and LINQ and async/await patterns Experince

Required

10

 

Solid software design: SOLID, design patterns, domain modeling, layered/clean architecture, dependency injection

Required

5

 

Angular 17+, Typescript and Node.js experience

Required

5

 

Strong relational database skills; PostgreSQL strongly preferred (Oracle/SQL Server acceptable) — schema design, indexing, query tuning, stored procedure

Required

5

 

unit/integration/regression testing frameworks; TDD/mocking

Required

5

 

Git and static code analysis (SonarQube)

Required

5

 

Docker containerization and CI/CD pipeline experience (AWS CODEPIPELINE OR GitHub Actions)

Required

3

 

AWS cloud native applications (S3, SNS, SQS, ECS, RDS, EC2, Lambda)

Required

3