How would you explain controllers and action results in an ASP.NET Core Web API?

For a create endpoint, I would validate CreateOrderRequest, call an application service, then return CreatedAtAction(nameof(GetById), new { id = order.Id }, response). That tells the client the resource was created and where to retrieve it.

• When would you return CreatedAtAction?
• Why avoid returning EF entities?
• How would you test a controller action?
• When would minimal APIs be a better fit?

Listen for thin-controller thinking and HTTP semantics. Good answers include DTOs, status codes, validation, and separation from application logic.

This is a practical ASP.NET Core question. Strong candidates describe controllers as API boundaries, not giant business-logic containers.