NET / .NET Core Full Stack Developer (Modernization)

Job Title: Senior .NET / .NET Core Full Stack Developer (Modernization)

Location: Philadelphia, PA 100% Onsite (No Remote/Hybrid)
Experience Required: 7+ years
Employment Type: Contract (W2 preferred)

Position Overview

We are seeking a Senior .NET / .NET Core Full Stack Developer to lead the modernization of legacy .NET applications into a scalable .NET Core microservices and modern web portal ecosystem. This role requires deep expertise in C#, .NET Core, MSSQL, and hands-on experience migrating databases to PostgreSQL on AWS RDS, along with strong AWS cloud and microservices experience.

Key Responsibilities

• Analyze legacy .NET Framework applications and define a modernization and migration strategy to .NET Core.

• Develop and modernize full-stack web portals and microservice-based backend components.

• Deeply analyze MSSQL schemas, stored procedures, triggers, and business logic, and translate them to PostgreSQL, optimizing for performance and compatibility.

• Execute database migration and transformation, including schema conversion, data migration, indexing, and tuning on PostgreSQL (AWS RDS).

• Design and build RESTful APIs ensuring scalability, modularity, and maintainability.

• Implement modern front-end components using React, Angular, or Vue.

• Collaborate with DevOps teams on AWS deployments, CI/CD pipelines, and environment automation.

• Apply AWS Well-Architected Framework principles to ensure secure, scalable, and cost-efficient solutions.

• Ensure best practices in security, cloud optimization, and application performance.

Technical Skills Required

Backend

• C#, .NET Framework, .NET Core, ASP.NET Core, Web API

• Entity Framework Core

Frontend

• React, Angular, or Vue (any modern JavaScript framework)

Database

• Strong MSSQL expertise (stored procedures, triggers, functions, performance tuning)

• Proven experience migrating MSSQL PostgreSQL

• PostgreSQL on AWS RDS

Architecture

• Microservices architecture

• RESTful APIs

• Domain-Driven Design (DDD)

• Dependency Injection

Cloud & DevOps

• AWS: EC2, RDS, S3, CloudWatch, API Gateway, Lambda, ECS/EKS

• Docker and containerization

• CI/CD: GitHub Actions, Jenkins, AWS CodePipeline

• IAM, VPC, networking fundamentals

Testing & Tools

• Swagger, Postman

• xUnit / NUnit

• Migration tools (AWS Schema Conversion Tool)

Version Control

• Git, GitHub

Preferred Qualifications

• AWS Certification (Developer Associate or Solutions Architect Associate)

• Experience modernizing monolithic systems to cloud-native microservices

• Serverless experience (AWS Lambda, API Gateway)

• Kubernetes experience

• Data migration tools: AWS DMS, pgLoader, Flyway, Liquibase

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