senior.NET Core

What is middleware in .NET Core?

Updated Feb 20, 2026

Short answer

Middleware are components that handle HTTP requests and responses in a pipeline.

Deep explanation

Each middleware can:

  • Process request
  • Call next middleware
  • Modify response

Execution order is critical and defined in Program.cs.

Real-world example

Authentication → Logging → Authorization → Controller

Common mistakes

  • - Wrong middleware order
  • - Not calling next()

Follow-up questions

  • How would you scale this?
  • What are trade-offs?
  • How would you debug production issues?
  • How does this compare to alternatives?

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