Astir IT Solutions, Inc. · 10 hours ago
Senior .NET / .NET Core Full Stack Developer (Modernization) Only w2
Philadelphia, PA
Contract
Onsite
Senior Level
7+ years expAstir IT Solutions, Inc. is seeking an experienced Full Stack Developer to drive the modernization of legacy .NET applications into a scalable .NET Core ecosystem. The role involves analyzing existing applications, developing modern web portals and microservices, and ensuring smooth database migration and integration across application layers.
Information TechnologyOutsourcingSoftware
Hiring Manager
Hari J
Responsibilities
Analyze 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
Qualification
Required
Minimum 7+ Years of Experience required
Strong background in both .NET Framework and .NET Core
Deep understanding of MSSQL databases
Capability of translating and optimizing MSSQL into PostgreSQL (AWS RDS)
Hands-on experience with AWS cloud deployment
Experience with microservices architecture
Analyze 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)
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
Backend: C#, .NET Framework, .NET Core, ASP.NET Core, Web API, Entity Framework Core
Frontend: React / Angular / Vue (any modern JavaScript framework)
Strong expertise in MSSQL — including stored procedures, triggers, functions, and performance tuning
Proven experience in translating MSSQL to PostgreSQL, including data type mapping, query optimization, and schema redesign
Hands-on experience with PostgreSQL on AWS RDS
Architecture: Microservices, RESTful APIs, Domain-Driven Design, Dependency Injection
Strong working knowledge of AWS services: EC2, RDS, S3, CloudWatch, API Gateway, Lambda, ECS/EKS
Experience deploying and managing .NET Core applications on AWS
Familiarity with IAM roles, VPC configuration, and networking basics
Experienced 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)
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
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
Company
Astir IT Solutions, Inc.
Astir IT Solutions, Inc. (www.astirit.com) is a fast growing IT consulting, services, and outsourcing firm.
201-500 employees
H1B Sponsorship
Astir IT Solutions, Inc. has a track record of offering H1B sponsorships. Please note that this does not
guarantee sponsorship for this specific role. Below presents additional info for your
reference. (Data Powered by US Department of Labor)
Distribution of Different Job Fields Receiving Sponsorship
Represents job field similar to this job
Trends of Total Sponsorships
2025 (119)
2024 (46)
2023 (67)
2022 (121)
2021 (117)
2020 (194)
Funding
Current Stage
Growth StageCompany data provided by crunchbase