NET Architect / Technical Lead - Mainframe Modernization

We are seeking a hands-on .NET Architect / Technical Lead to lead the modernization of legacy mainframe applications into secure, scalable, and maintainable .NET applications on AWS. The role requires strong expertise in C#, modern .NET, Blazor, SQL Server, and AWS. The candidate will own application architecture, hands-on development, technical delivery, and modernization quality while collaborating with mainframe specialists, UX designers, and business stakeholders. Prior mainframe modernization experience is preferred but not mandatory., * Lead architecture, design, and hands-on development using C#, .NET 10, ASP.NET Core, and Blazor.

• Apply domain-driven design (DDD) to define business domains and appropriate modular or microservices architectures.
• Design REST APIs, asynchronous workflows, messaging integrations, and resilient distributed applications.
• Modernize legacy mainframe screens into intuitive, responsive Blazor-based applications, improving user experience rather than simply replicating existing screens.
• Collaborate with mainframe SMEs to understand COBOL programs, CICS transactions, JCL jobs, business rules, data structures, and application dependencies.
• Ensure functional equivalence between legacy and modernized applications through automated regression testing, output comparison, and data reconciliation.
• Design and deploy applications on AWS using appropriate services such as ECS/Fargate, Lambda, RDS SQL Server, S3, SQS, EventBridge, and Step Functions.
• Lead SQL Server database design, data migration, query optimization, and transaction management.
• Modernize batch processing and file-based integrations with scheduling, restartability, and exception handling.
• Implement application security, authentication, role-based authorization, audit logging, and AWS IAM controls.
• Establish CI/CD pipelines, infrastructure as code, automated testing, monitoring, and observability.
• Lead technical reviews, mentor developers, resolve complex issues, and ensure engineering quality.
• Support migration planning, parallel validation, production cutover, rollback, and operational handover.
• Evaluate and use AI-assisted development and modernization tools with appropriate validation and quality controls.

Experience: 10+ years of software development experience, including 3+ years in technical leadership or architecture roles. Type: Hybrid, * 10+ years of software development experience, including 3+ years in technical leadership or architecture roles.

• Strong hands-on expertise in C#, ASP.NET Core, modern .NET, and enterprise application architecture.
• Production experience with Blazor, including reusable components, forms, validation, state management, and API integration.
• Strong understanding of domain-driven design, REST APIs, modular architecture, and microservices.
• Experience designing, deploying, and supporting production applications on AWS.
• Strong SQL Server skills, including schema design, query optimization, indexing, and transaction management.
• Experience with Entity Framework Core, Dapper, or equivalent data access technologies.
• Experience with distributed systems, asynchronous messaging, resiliency, and transaction consistency.
• Experience with Docker, CI/CD pipelines, Git, and infrastructure as code.
• Strong understanding of application security, authentication, authorization, and automated testing.
• Ability to lead architecture decisions, mentor engineers, and remain hands-on with development and troubleshooting., * Experience modernizing mainframe or other legacy enterprise applications.
• Familiarity with COBOL, JCL, CICS, VSAM, copybooks, and legacy data formats such as EBCDIC and packed decimal.
• Experience with AWS Transform for mainframe or equivalent modernization tools.
• Experience with Amazon RDS for SQL Server, ECS/Fargate, Lambda, SQS, EventBridge, and Step Functions.
• Experience with functional-equivalence testing, batch reconciliation, parallel runs, and migration cutover.
• Experience with Terraform, AWS CDK, CloudFormation, Azure DevOps, or GitHub Actions.
• Experience using AI-assisted development or code-conversion tools.

Ideal Candidate

A hands-on architect and technical leader who can take ownership of modernization delivery from design through production. Someone who can translate complex legacy functionality into modern .NET applications, make sound architectural decisions, lead developers, and ensure the modernized solution preserves business functionality while improving usability, scalability, and maintainability.