Senior .NET / .NET Core Full Stack Developer (Modernization)

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

Location: Philadelphia, PA

Mode: Contract

Domain: Telecom Domain Mandatory

Experience:

7+ years Overview We are looking for an experienced Full Stack Developer with a strong background in both .NET Framework and .NET Core, who can drive the modernization of legacy .NET applications into a scalable .NET Core microservices and web portal ecosystem.

The ideal candidate should have a deep understanding of MSSQL databases, be capable of translating and optimizing them into PostgreSQL (AWS RDS), and ensure smooth migration and integration across application layers, along with hands-on experience with AWS cloud deployment, microservices architecture.

Key Responsibilities

• Analyse existing legacy .NET applications and define a modernization and migration strategy to .NET Core.
• Develop and modernize both full-stack web portals and microservice-based components using .NET Core.
• Deeply understand existing MSSQL schema, stored procedures, and business logic, and effectively translate them to PostgreSQL, optimizing for performance and compatibility.
• Handle database migration and transformation including schema conversion, data migration, indexing, and tuning in PostgreSQL (AWS RDS).
• Design and build RESTful APIs and backend services, ensuring modularity and maintainability.
• Implement front-end components using modern JavaScript frameworks (React / Angular / Vue). [Will get more information with SOW]
• Collaborate with DevOps for AWS-based deployment, CI/CD pipeline setup, and environment automation.
• Ensure best practices in security, scalability, and cloud optimization throughout the modernization process.
• Apply AWS Well-Architected Framework principles for reliable and cost-efficient cloud solutions. Technical Skills Required
• Backend: C#, .NET Framework, .NET Core, ASP.NET Core, Web API, Entity Framework Core.
• Frontend: React / Angular / Vue (any modern JavaScript framework).
• Database:

o Strong expertise in MSSQL including stored procedures, triggers, functions, and performance tuning. o Proven experience in translating MSSQL to PostgreSQL, including data type mapping, query optimization, and schema redesign.

o Hands-on experience with PostgreSQL on AWS RDS.

• Architecture: Microservices, RESTful APIs, Domain-Driven Design, Dependency Injection.
• Cloud & DevOps:

o Strong working knowledge of AWS services: EC2, RDS, S3, CloudWatch, API Gateway, Lambda, ECS/EKS. o Experience deploying and managing .NET Core applications on AWS.

o Familiarity with IAM roles, VPC configuration, and networking basics.

o Experienced with with Docker, CI/CD (GitHub Actions, Jenkins, AWS CodePipeline).

• Version Control: Git, GitHub.
• Testing & Tools: Swagger / Postman, xUnit / NUnit, migration tools (e.g., AWS Schema Conversion Tool). Preferred:
• AWS Certification (Developer Associate / Solutions Architect Associate).
• Experience in modernizing monolithic systems to cloud-native microservices.
• Experienced with serverless (AWS Lambda) and API Gateway integrations.
• Familiarity with containerization (Docker, Kubernetes).
• Experience with data migration utilities (AWS DMS, pgLoader, Flyway, Liquibase).
• Knowledge of Agile/Scrum development processes. Soft Skills:
• Strong analytical ability to understand legacy codebases and re-engineer them effectively.
• Excellent problem-solving and debugging skills across both application and database layers.
• Strong communication skills to work with cross-functional teams and stakeholders.
• Self-driven and ownership-oriented with a continuous learning mindset.