As a Principal Software Developer at Solar Turbines, you will design, develop, and implement modern software tools using Agile methodologies, collaborating with cross-functional teams on product design, testing, and validation. You'll modernize legacy software and mentor team members, requiring 7+ years of experience with C#, VB.NET, Python, TypeScript, and .NET framework, plus hands-on expertise in Oracle or SQL database design. Desktop application development using WinUI or XAML frameworks is essential, along with proficiency in ORM tools like Entity Framework and Dapper. You'll work with front-end technologies (ReactJS, Angular v17+), API development, middleware, and token-based authentication in a 5-day-per-week on-site role in San Diego.