ASP.NET Core Middleware - Documentation

Overview

ASP.NET Core middleware are software components assembled into an application pipeline to handle requests and responses. Each component can:

Perform actions before and after the next component in the pipeline.
Short‑circuit the pipeline to produce a response.
Invoke the next component via await next(context).

Key concepts

Concept	Description
RequestDelegate	Represents the next middleware in the pipeline.
HttpContext	Encapsulates all HTTP-specific information about an individual HTTP request.
Use/Run	Extension methods on `IApplicationBuilder` to add middleware.
Terminal middleware	Middleware that does not call `next()`, ending the pipeline.

Getting started

To add middleware, use the Configure method in Startup.cs (or Program.cs in minimal hosting):

var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();

app.UseHttpsRedirection();
app.UseStaticFiles();
app.UseRouting();

app.UseAuthentication();
app.UseAuthorization();

app.UseEndpoints(endpoints =>
{
    endpoints.MapControllers();
});

app.Run();

Read the Creating Middleware page for a step‑by‑step guide on building custom middleware.