$110K - 140K a year
Upgrade and refactor legacy .NET applications, debug frontend and backend layers, optimize SQL Server databases, and collaborate on modernizing front-end components.
7+ years experience with C#, .NET, ASP.NET MVC, Microsoft SQL Server, Entity Framework, JavaScript/jQuery, and API security protocols.
We are seeking a Senior Software Engineer to support the modernization and migration of a legacy application stack. The ideal candidate will have an extensive background in C# .NET, ASP.NET MVC, and Microsoft SQL Server, with hands-on experience in upgrading and refactoring enterprise applications. Responsibilities: • Upgrade and refactor legacy .NET applications (currently on .NET Framework 4.x / ASP.NET MVC 5) to .NET 9. • Debug and maintain application layers: frontend (JavaScript/jQuery), middle tier (C#), and database (SQL Server). • Write and optimize complex SQL queries and views across large-scale schemas (100,000+ tables). • Work with Entity Framework to manage data access and persistence. • Analyze and apply indexing strategies, query optimizations, and understand use of SQL optimizers. • Apply table normalization, aggregation techniques, joins, and table hints in SQL Server. • Utilize SOLID design principles in software architecture when appropriate. • Ensure API security using OAuth, token-based authentication, and related standards. • Collaborate with teams to modernize front-end components and explore modern JavaScript libraries/frameworks. Required Skills & Qualifications: • 7+ years of experience creating web applications with C#, .NET, and ASP.NET MVC. • Proficient with Microsoft SQL Server, including complex views, stored procedures, etc. • Professional experience using Entity Framework. • Solid experience debugging across frontend, business logic, and data layers. • Knowledge of indexing, query optimization, and execution plans. • Proficient with JavaScript and jQuery. • Experience implementing and maintaining OAuth, tokens, and API security protocols. Nice to Have: • Experience with Azure, Azure SQL, and Azure Functions. • Proficiency creating single-page web applications using modern JavaScripts libraries and/or frameworks such as React.js, Node.js, Angular, etc. • Understanding of cloud migrations and version control systems in the cloud.
This job posting was last updated on 10/18/2025