But, Matt data annotations are for validations on the view side and nothing to do with your BL/service layer. Basically in MVC, models are responsible data validations. I would still do the required validations on my BL/service side (required, null, etc.)

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Hi Matt, If I get you correctly then are pointing towards that if you have BL or service layer then you would do away with Model? Correct me if I'm wrong. But, please note that model is the manifestation of your view i.e. it is tightly coupled to your view. You should have that as well as Business layer where you would get the data (from DAL), do some processing and then pass the data onto the model. Also, note that model does not do away DTO as well which would be used to communicate between your various layers. A lot of the time DTO and models are pretty much the same but can differ based on the requirements.

Hope this helps, if it does then mark it as answer Rohit Aanstaande blog sweet blog