Senior Full-Stack .NET Developer

Resolution Technologies, Inc.; Atlanta (GA); On-site; USD 120,000 - 160,000; Full time

Job summary

Resolution Technologies, Inc. is seeking a Senior Full-Stack .NET Developer to lead a major modernization from legacy ASP.NET to .NET 8+, Azure services, and a React UI. You will own design decisions, architecture, and delivery from concept to production.

You will build API-first services, manage SQL Server data, implement CI/CD with Azure DevOps, and guide the team through architecture reviews and sprints. Strong experience migrating apps and delivering secure, scalable solutions is required.

Qualifications

• 8+ years of professional .NET development experience (C#, ASP.NET MVC, Web API).
• Experience migrating legacy ASP.NET applications to modern .NET (6, 7, 8 or 10).
• Production SQL Server experience: stored procedures, T-SQL tuning, schema migrations, data clean-up.
• 5+ years delivering software in Agile environments using ADO or GitHub.
• You have modernized a real application - not a proof of concept - from legacy ASP.NET to .NET 6/7/8/10.
• You have designed and maintained RESTful APIs that external systems depend on.

Responsibilities

• Modernize licensing applications to .NET and Azure-based architectures.
• Design scalable, secure, maintainable solutions that reduce technical debt.
• Build API-first integrations and services for future platform capabilities.
• Develop cloud-native solutions using Azure App Services and Functions.
• Own the SQL Server platform including data architecture and performance tuning.
• Implement CI/CD pipelines with Azure DevOps for automated testing and deployment.
• Drive engineering excellence through code reviews and documentation.
• Build and maintain React-based UI components.
• Participate in architecture and code reviews and sprint ceremonies.

Skills

C#

ASP.NET MVC

Web API

Agile

RESTful APIs

Education

Bachelor's degree in Computer Science or related field

Tools

Azure DevOps

GitHub

SQL Server

React

Power BI

Job description

Senior Full-Stack .NET Developer Job Overview

The Senior Full-Stack .NET Developer will be involved in a major modernization effort, moving a mission critical online, self-service portal from a legacy ASP.NET architecture to .NET 8+, modern APIs, Azure cloud services, and a React-based user experience. This is not a maintenance or production support role. This position is for a senior engineer who wants to lead modernization efforts, solve complex technical problems, and help shape the future architecture of an enterprise platform. You will play a key role in technical design decisions, application architecture, cloud integration, and delivery. Our team is intentionally lean. That means ownership matters. You will be expected to take a solution from concept to production, including design, development, testing, deployment, documentation, and operational support. Success in this role requires initiative, accountability, and the ability to work independently. If you enjoy building, leading, and owning outcomes, you will thrive here.

Senior Full-Stack .NET Developer Role and Responsibilities

• Application Modernization (Primary Focus):Champion the modernization of mission-critical licensing and eligibility applications, transitioning legacy solutions to modern .NET and Azure-based architectures.
• Design and implement scalable, secure, and maintainable application solutions that reduce technical debt and improve long-term supportability.
• Build and evolve API-first integrations and services that enable future platform capabilities.
• Develop cloud-native solutions using Azure App Services, Azure Functions, and related Azure technologies.
• Own the SQL Server platform, including data architecture, performance tuning, data migration, and platform modernization.
• Implement and maintain CI/CD pipelines using Azure DevOps to automate testing, deployment, and release management.
• Drive engineering excellence through code reviews, automation, documentation, and adherence to modern development practices.
• Frontend and Integration:Build and maintain React-based UI components as part of the modernization roadmap.
• Demonstrate a strong understanding of web application rendering patterns, including client-side rendering (CSR), server-side rendering (SSR), component-based architectures, and modern frontend frameworks.
• Integrate third-party services and internal APIs; document every integration cleanly.
• Implement and maintain reporting using SSRS and Power BI.
• Participate in AI integration initiatives - Azure Agentic AI services, Copilot tooling, and chatbot integrations where applicable.
• Quality, Documentation, and Support:Write code that your teammates can read and maintain in the future.
• Provide production support and own root-cause analysis when things break.
• Maintain application documentation, deployment runbooks, and user-facing guides.
• Participate in architecture reviews, code reviews, and sprint ceremonies.

Senior Full-Stack .NET Developer Required Skills and Qualifications

• 8+ years of professional .NET development experience - C#, ASP.NET MVC, Web API.
• Demonstrated, hands-on experience migrating legacy ASP.NET applications to modern .NET (6, 7, 8 or 10).
• Production SQL Server experience: stored procedures, T-SQL tuning, schema migrations, data clean-up.
• 5+ years of delivering software in Agile (Scrum or Kanban) environments using ADO or GitHub.
• You have modernized a real application - not a proof of concept - from legacy ASP.NET to .NET 6/7/8/10.
• You have designed and maintained RESTful APIs that external systems depend on.
• You have debugged production issues independently, without a team lead walking you through it.

Senior Full-Stack .NET Developer Preferred Skills and Qualifications

• React experience, specifically building components within an existing application, not greenfield.
• Exposure to .NET 10.
• Experience with government, healthcare, or public-sector systems. Strong understanding of compliance, auditability, and data sensitivity.
• Familiarity with ADA/WCAG 2.1 AA accessibility standards.
• Exposure to Azure Agentic AI services or integration of AI-driven features in production applications.
• Experience with middleware platforms such as Boomi or MuleSoft.
• Background working with PII data and the security protocols that protect it.

Senior Full-Stack .NET Developer Education

• Bachelor degree in Computer Science, Information Technology, or a related field.