All 15 Global Exception Handling & Middleware questions
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What is the purpose of global exception handling middleware in an ASP.NET Core application? How does the IExceptionHandler interface (introduced in .NET 8) provide a more structured alternative to the UseExceptionHandler lambda approach? How do you map different exception types to different HTTP status codes in a global exception handler? How do you handle exceptions specifically within minimal API endpoints, given they don't use the traditional MVC exception filter pipeline? What is the difference between handling exceptions with middleware versus using try/catch blocks directly in controller actions? How should a global exception handler differentiate between exceptions that should return specific client-facing details versus exceptions that should always show a generic message? What is the role of the [ApiController] attribute in automatically handling certain error scenarios without explicit exception handling code? How do you write an integration test verifying that your global exception handler produces the correct error response shape? What is ProblemDetails (RFC 7807/9457), and how does ASP.NET Core support it for standardized error responses? What information should be excluded from error responses in production to avoid leaking sensitive implementation details?
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.NET › Global Exception Handling & Middleware

What happens by default in ASP.NET Core if you don't configure any global exception handling middleware at all?

Beginner

Answer

Without any exception handling middleware configured, an unhandled exception propagates all the way up through Kestrel, resulting in either a bare 500 Internal Server Error with no body (in Production) or, if UseDeveloperExceptionPage is active, a detailed HTML error page showing the full stack trace -- neither is appropriate for a real production API, which is why configuring at least a basic UseExceptionHandler is considered essential baseline setup for any API expected to run in production.
// With NO exception handling middleware configured:
// An unhandled exception results in a generic 500 with an empty or minimal body
// -- no consistent JSON error format, no logging guarantee, no safe error message
Real-world example A newly bootstrapped API prototype that skipped configuring UseExceptionHandler entirely is caught in code review before its first production deployment, since every unhandled exception would otherwise return an unhelpful bare 500 response to API consumers.

Common follow-ups: What's the minimum viable exception handling setup for a new ASP.NET Core API?;Why does Kestrel itself not provide a default JSON error format?

Global Exception Handling & Middleware;ASP.NET Core Middleware & Request Pipeline
All 15 Global Exception Handling & Middleware questions