Error handling / global exception handling in APIs?

Short answer: Use UseExceptionHandler middleware or custom ExceptionMiddleware. You can also create a global error handler: app.UseExceptionHandler(config => { config.Run(async context => { // Log and return problem details }); }); Or use ProblemDetails for structured error responses.

Real-world example (ShopNest)

A ShopNest ValidateModelAttribute runs before actions and returns 400 if ModelState is invalid—same rule for every controller.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.