Using exception handlers in an ASP.NET Core Web API

Learn how to add exception handlers in an ASP.NET Core Web API.

You can read more about exception handlers, or watch the video:

Download the code example

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Software

This is the software that will need to be installed onto your machine.

• Visual Studio 2026. Version 18.0.0 or above. It will work with the free community version.

• .NET 10 SDK. Version 10.0.0 or above.

The application

Open up RoundTheCode.ExceptionHandlerSetup.slnx, and run the application. The Swagger documentation will load at https://localhost:7009/swagger with these endpoints:

• /api/products/validation-exception (POST) - Throws a 400 Bad Request response. Try it with this request body:

  {
  	"name": "",
  	"price": -0.1
  }

• /api/products/unauthorized-exception (POST) - Throws a 401 Unauthorized response.

• /api/products/global-exception (POST) - Throws a 500 Internal Server error response.

If you want to try out the exception handler in ExceptionHandlingMiddleware, uncomment it in Program.cs.