A Professional ASP.NET Core API - FluentValidation
FluentValidation is a A .NET library for building strongly-typed validation rules. It uses lambda expressions for building validation rules for your business objects.
If you want to do simple validation in asp.net mvc application then data annotations validation is good but in case if you want to implement complex validation then you need to use FluentValidation.
In the following we will see how it can be added to a project and how it works.