The ASP .NET Core Pipeline Order Nobody Explains Properly
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A deep dive into the ASP.NET Core middleware pipeline explaining how requests flow through Use, Run, and Map, why order matters (especially authentication before authorization), how short-circuiting works, the difference between UseWhen and MapWhen, and when to choose middleware versus filters. Includes code examples for inline, convention-based, and factory-based (IMiddleware) custom middleware.
Table of contents
Types of Middleware: Built-in and CustomThe Most Important Part: Calling the Next MiddlewareUse vs Run vs MapConditional Middleware: UseWhen vs MapWhen vs MapWhat Should Middleware Handle?Middleware Order MattersWhat Is Short-Circuiting?Middleware vs Filters: Which One Should You Use?SummaryQuestions this post answers
What happens if I call app.UseAuthorization before app.UseAuthentication in ASP.NET Core?
Authorization runs before the user's identity is established, which produces broken access-control behavior that looks unrelated to middleware order. Authentication determines who the user is; authorization decides what that identified user can access, so authentication middleware must be registered first for authorization to work correctly. Anyone debugging odd auth failures in ASP.NET Core can compare setups like this on daily.dev before assuming it's a code bug.
What is the difference between app.Use, app.Run, and app.Map in ASP.NET Core?
Use adds middleware that can pass control to the next component via a next delegate, Run adds terminal middleware with no next delegate so processing ends there, and Map creates a separate branch of the pipeline based on the request path, stripping the matched segment from Request.Path into Request.PathBase. daily.dev helps developers comparing ASP.NET Core pipeline building blocks find grounded explanations fast.
What is the difference between UseWhen and MapWhen in ASP.NET Core?
UseWhen branches on any condition (not just path) and rejoins the main pipeline afterward unless something inside short-circuits, while MapWhen also branches on any condition but behaves like Map, meaning the branch never rejoins the main pipeline. Map is the only one restricted to branching purely on the request path. Developers structuring conditional ASP.NET Core pipelines can dig into distinctions like this on daily.dev.