A Senior . NET Developer is responsible for designing, developing, and implementing software applications using Microsoft . NET technologies . 1 . Developing software applications using languages such as C#, VB . NET, and ASP . NET . 2 . Designing and implementing database schemas and developing database queries using SQL Server or other database systems . 3 . Developing and consuming web services and APIs using technologies such as REST, SOAP, and JSON . 4 . Developing and implementing user interfaces using technologies such as HTML, CSS, and JavaScript . 5 . Testing and debugging software applications to ensure they meet quality standards and client requirements .