All 15 Global Exception Handling & Middleware questions
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What happens by default in ASP.NET Core if you don't configure any global exception handling middleware at all? 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 is the purpose of global exception handling middleware in an ASP.NET Core application?

Beginner

Answer

Global exception handling middleware catches unhandled exceptions thrown anywhere downstream in the pipeline (controllers, other middleware, business logic), preventing them from crashing the request or leaking a raw stack trace to clients, and instead converting them into a consistent, well-formed error response (like a standardized JSON error body with an appropriate HTTP status code) -- centralizing error-handling logic in one place instead of scattering try/catch blocks throughout every controller action.
app.UseExceptionHandler("/error");  // catches any unhandled exception from everything after this line

app.Map("/error", (HttpContext context) => {
    return Results.Problem(title: "An error occurred", statusCode: 500);
});
Real-world example Without global exception handling, a single unhandled null reference exception deep in business logic would return a raw ASP.NET Core error page (or worse, an unhandled crash) instead of the consistent JSON error format all API consumers expect.

Common follow-ups: How does UseExceptionHandler differ from the newer IExceptionHandler interface in .NET 8?;What information should and shouldn't be included in an error response for security reasons?

ASP.NET Core Middleware & Request Pipeline;RESTful Web APIs & Controllers
All 15 Global Exception Handling & Middleware questions