A Blazor .NET Developer is responsible for building interactive web applications using Blazor, a framework that allows developers to create web UIs with C# and .NET instead of JavaScript. They work with technologies like Razor components, WebAssembly, and server-side rendering to develop modern web applications. These developers require expertise in .NET, C#, HTML, CSS, and often integrate REST APIs and databases into their applications. Their role includes coding, debugging, optimizing performance, and ensuring a responsive user experience.