ASP.NET

ASP.NET is Microsoft's web framework for building web applications, HTTP APIs and real-time services on the .NET platform, primarily in C#. The name covers two generations: the legacy, Windows-only ASP.NET Framework (Web Forms, MVC 5) and ASP.NET Core — a ground-up, open-source rewrite that runs cross-platform and is where all current development happens.

How ASP.NET works

An ASP.NET Core application is a self-contained .NET process with an embedded high-performance HTTP server called Kestrel. Each incoming request flows through a configurable middleware pipeline — routing, authentication, compression, error handling — before reaching application logic. Developers choose among several programming models:

• MVC and Razor Pages — server-rendered HTML views with strongly typed templates;
• Web API and Minimal APIs — lean REST endpoints returning JSON, with the minimal style reducing boilerplate to a few lines;
• Blazor — interactive UIs written in C# instead of JavaScript, rendered on the server or in the browser via WebAssembly;
• SignalR — real-time messaging over WebSockets with automatic fallbacks.

Built-in dependency injection, static typing and ahead-of-time compilation options make ASP.NET Core one of the fastest mainstream web frameworks in independent benchmarks.

Practical application

ASP.NET is a staple of enterprise software: financial systems, ERP platforms, internal portals, and large APIs backing mobile and desktop clients, especially in organizations already invested in the Microsoft ecosystem — Azure, SQL Server, Active Directory. The tooling (Visual Studio, Entity Framework Core) and long-term support releases suit projects measured in years, maintained by changing teams.

Deployment today usually means Linux: the app runs as a systemd service or a Docker container behind an Nginx reverse proxy, so an ordinary Linux VPS with the .NET runtime installed is a perfectly standard production home. Windows hosting with IIS remains relevant mainly for legacy ASP.NET Framework applications that were never migrated.