Domain Validation in a CQRS architecture

Question

Danger ... Danger Dr. Smith... Philosophical post ahead

The purpose of this post is to determine if placing the validation logic outside of my domain entiti

Answer 1

You can use a message based solution with Domain Events as explained here.

Exceptions are not the right method for all validation errors, is not said that a not valid entity is an exceptional case.

If the validation is not trivial, the logic to validate the aggregate can be executed directly on the server and while you are trying to set new input you can raise a Domain Event to tell to the user (or the application that is using your domain) why the input is not correct.